This mod makes slabs feel complete and adds functionality to them that I feel like should be in the base game.

Stack different slabs on top of each other

These double slab blocks calculate their hardness based on the slabs they are built from
When mined they drop the slabs they are built from
For this to work the slab must be in the slabs.json tag

Slab variants for every block

They try to keep their properties like hardness, explosion resistance, and luminance
You get them by crafting them in the stonecutter

BLOCK IDs:
"slabsexpanded:soul_sand_slab",
"slabsexpanded:glass_slab",
"slabsexpanded:white_stained_glass_slab",
"slabsexpanded:orange_stained_glass_slab",
"slabsexpanded:magenta_stained_glass_slab",
"slabsexpanded:light_blue_stained_glass_slab",
"slabsexpanded:yellow_stained_glass_slab",
"slabsexpanded:lime_stained_glass_slab",
"slabsexpanded:pink_stained_glass_slab",
"slabsexpanded:gray_stained_glass_slab",
"slabsexpanded:light_gray_stained_glass_slab",
"slabsexpanded:cyan_stained_glass_slab",
"slabsexpanded:purple_stained_glass_slab",
"slabsexpanded:blue_stained_glass_slab",
"slabsexpanded:brown_stained_glass_slab",
"slabsexpanded:green_stained_glass_slab",
"slabsexpanded:red_stained_glass_slab",
"slabsexpanded:black_stained_glass_slab",
"slabsexpanded:dead_tube_coral_block_slab",
"slabsexpanded:dead_brain_coral_block_slab",
"slabsexpanded:dead_bubble_coral_block_slab",
"slabsexpanded:dead_fire_coral_block_slab",
"slabsexpanded:dead_horn_coral_block_slab",
"slabsexpanded:tube_coral_block_slab",
"slabsexpanded:brain_coral_block_slab",
"slabsexpanded:bubble_coral_block_slab",
"slabsexpanded:fire_coral_block_slab",
"slabsexpanded:horn_coral_block_slab",
"slabsexpanded:gold_ore_slab",
"slabsexpanded:deepslate_gold_ore_slab",
"slabsexpanded:iron_ore_slab",
"slabsexpanded:deepslate_iron_ore_slab",
"slabsexpanded:coal_ore_slab",
"slabsexpanded:deepslate_coal_ore_slab",
"slabsexpanded:nether_gold_ore_slab",
"slabsexpanded:sponge_slab",
"slabsexpanded:wet_sponge_slab",
"slabsexpanded:lapis_ore_slab",
"slabsexpanded:deepslate_lapis_ore_slab",
"slabsexpanded:lapis_block_slab",
"slabsexpanded:gold_block_slab",
"slabsexpanded:iron_block_slab",
"slabsexpanded:bookshelf_slab",
"slabsexpanded:diamond_ore_slab",
"slabsexpanded:deepslate_diamond_ore_slab",
"slabsexpanded:diamond_block_slab",
"slabsexpanded:clay_slab",
"slabsexpanded:basalt_slab",
"slabsexpanded:polished_basalt_slab",
"slabsexpanded:glowstone_slab",
"slabsexpanded:carved_pumpkin_slab",
"slabsexpanded:jack_o_lantern_slab",
"slabsexpanded:oxidized_copper_slab",
"slabsexpanded:weathered_copper_slab",
"slabsexpanded:exposed_copper_slab",
"slabsexpanded:copper_block_slab",
"slabsexpanded:waxed_copper_block_slab",
"slabsexpanded:waxed_weathered_copper_slab",
"slabsexpanded:waxed_exposed_copper_slab",
"slabsexpanded:waxed_oxidized_copper_slab",
"slabsexpanded:white_terracotta_slab",
"slabsexpanded:cracked_stone_bricks_slab",
"slabsexpanded:chiseled_stone_bricks_slab",
"slabsexpanded:mud_bricks_slab",
"slabsexpanded:brown_mushroom_block_slab",
"slabsexpanded:red_mushroom_block_slab",
"slabsexpanded:mushroom_stem_slab",
"slabsexpanded:melon_slab",
"slabsexpanded:end_stone_slab",
"slabsexpanded:emerald_ore_slab",
"slabsexpanded:deepslate_emerald_ore_slab",
"slabsexpanded:emerald_block_slab",
"slabsexpanded:command_block_slab",
"slabsexpanded:nether_quartz_ore_slab",
"slabsexpanded:quartz_pillar_slab",
"slabsexpanded:orange_terracotta_slab",
"slabsexpanded:magenta_terracotta_slab",
"slabsexpanded:light_blue_terracotta_slab",
"slabsexpanded:yellow_terracotta_slab",
"slabsexpanded:lime_terracotta_slab",
"slabsexpanded:pink_terracotta_slab",
"slabsexpanded:gray_terracotta_slab",
"slabsexpanded:light_gray_terracotta_slab",
"slabsexpanded:cyan_terracotta_slab",
"slabsexpanded:purple_terracotta_slab",
"slabsexpanded:blue_terracotta_slab",
"slabsexpanded:brown_terracotta_slab",
"slabsexpanded:green_terracotta_slab",
"slabsexpanded:red_terracotta_slab",
"slabsexpanded:black_terracotta_slab",
"slabsexpanded:sea_lantern_slab",
"slabsexpanded:hay_block_slab",
"slabsexpanded:terracotta_slab",
"slabsexpanded:coal_block_slab",
"slabsexpanded:packed_ice_slab",
"slabsexpanded:chiseled_red_sandstone_slab",
"slabsexpanded:purpur_pillar_slab",
"slabsexpanded:redstone_block_slab",
"slabsexpanded:slime_block_slab",
"slabsexpanded:magma_block_slab",
"slabsexpanded:nether_wart_block_slab",
"slabsexpanded:bone_block_slab",
"slabsexpanded:white_concrete_slab",
"slabsexpanded:orange_concrete_slab",
"slabsexpanded:magenta_concrete_slab",
"slabsexpanded:light_blue_concrete_slab",
"slabsexpanded:yellow_concrete_slab",
"slabsexpanded:lime_concrete_slab",
"slabsexpanded:pink_concrete_slab",
"slabsexpanded:gray_concrete_slab",
"slabsexpanded:light_gray_concrete_slab",
"slabsexpanded:cyan_concrete_slab",
"slabsexpanded:purple_concrete_slab",
"slabsexpanded:blue_concrete_slab",
"slabsexpanded:brown_concrete_slab",
"slabsexpanded:green_concrete_slab",
"slabsexpanded:red_concrete_slab",
"slabsexpanded:black_concrete_slab",
"slabsexpanded:white_concrete_powder_slab",
"slabsexpanded:orange_concrete_powder_slab",
"slabsexpanded:magenta_concrete_powder_slab",
"slabsexpanded:light_blue_concrete_powder_slab",
"slabsexpanded:yellow_concrete_powder_slab",
"slabsexpanded:lime_concrete_powder_slab",
"slabsexpanded:pink_concrete_powder_slab",
"slabsexpanded:gray_concrete_powder_slab",
"slabsexpanded:light_gray_concrete_powder_slab",
"slabsexpanded:cyan_concrete_powder_slab",
"slabsexpanded:purple_concrete_powder_slab",
"slabsexpanded:blue_concrete_powder_slab",
"slabsexpanded:brown_concrete_powder_slab",
"slabsexpanded:red_concrete_powder_slab",
"slabsexpanded:green_concrete_powder_slab",
"slabsexpanded:black_concrete_powder_slab",
"slabsexpanded:dried_kelp_block_slab",
"slabsexpanded:blue_ice_slab",
"slabsexpanded:warped_stem_slab",
"slabsexpanded:stripped_warped_stem_slab",
"slabsexpanded:warped_hyphae_slab",
"slabsexpanded:stripped_warped_hyphae_slab",
"slabsexpanded:warped_nylium_slab",
"slabsexpanded:warped_wart_block_slab",
"slabsexpanded:crimson_stem_slab",
"slabsexpanded:stripped_crimson_stem_slab",
"slabsexpanded:crimson_hyphae_slab",
"slabsexpanded:stripped_crimson_hyphae_slab",
"slabsexpanded:shroomlight_slab",
"slabsexpanded:crimson_nylium_slab",
"slabsexpanded:honey_block_slab",
"slabsexpanded:honeycomb_block_slab",
"slabsexpanded:netherite_block_slab",
"slabsexpanded:ancient_debris_slab",
"slabsexpanded:crying_obsidian_slab",
"slabsexpanded:cracked_polished_blackstone_bricks_slab",
"slabsexpanded:chiseled_polished_blackstone_slab",
"slabsexpanded:gilded_blackstone_slab",
"slabsexpanded:chiseled_nether_bricks_slab",
"slabsexpanded:cracked_nether_bricks_slab",
"slabsexpanded:quartz_bricks_slab",
"slabsexpanded:amethyst_block_slab",
"slabsexpanded:budding_amethyst_slab",
"slabsexpanded:tuff_slab",
"slabsexpanded:calcite_slab",
"slabsexpanded:sculk_slab",
"slabsexpanded:moss_block_slab",
"slabsexpanded:rooted_dirt_slab",
"slabsexpanded:mud_slab",
"slabsexpanded:chiseled_deepslate_slab",
"slabsexpanded:cracked_deepslate_bricks_slab",
"slabsexpanded:smooth_basalt_slab",
"slabsexpanded:raw_iron_block_slab",
"slabsexpanded:raw_copper_block_slab",
"slabsexpanded:raw_gold_block_slab",
"slabsexpanded:ochre_froglight_slab",
"slabsexpanded:verdant_froglight_slab",
"slabsexpanded:pearlescent_froglight_slab",
"slabsexpanded:reinforced_deepslate_slab",
"slabsexpanded:redstone_ore_slab",
"slabsexpanded:deepslate_redstone_ore_slab",
"slabsexpanded:grass_block_slab",
"slabsexpanded:oak_log_slab",
"slabsexpanded:spruce_log_slab",
"slabsexpanded:birch_log_slab",
"slabsexpanded:jungle_log_slab",
"slabsexpanded:acacia_log_slab",
"slabsexpanded:cherry_log_slab",
"slabsexpanded:dark_oak_log_slab",
"slabsexpanded:mangrove_log_slab",
"slabsexpanded:bamboo_block_slab",
"slabsexpanded:stripped_spruce_log_slab",
"slabsexpanded:stripped_birch_log_slab",
"slabsexpanded:stripped_jungle_log_slab",
"slabsexpanded:stripped_acacia_log_slab",
"slabsexpanded:stripped_cherry_log_slab",
"slabsexpanded:stripped_dark_oak_log_slab",
"slabsexpanded:stripped_oak_log_slab",
"slabsexpanded:stripped_mangrove_log_slab",
"slabsexpanded:stripped_bamboo_block_slab",
"slabsexpanded:oak_wood_slab",
"slabsexpanded:spruce_wood_slab",
"slabsexpanded:birch_wood_slab",
"slabsexpanded:jungle_wood_slab",
"slabsexpanded:acacia_wood_slab",
"slabsexpanded:cherry_wood_slab",
"slabsexpanded:dark_oak_wood_slab",
"slabsexpanded:mangrove_wood_slab",
"slabsexpanded:stripped_oak_wood_slab",
"slabsexpanded:stripped_spruce_wood_slab",
"slabsexpanded:stripped_birch_wood_slab",
"slabsexpanded:stripped_jungle_wood_slab",
"slabsexpanded:stripped_acacia_wood_slab",
"slabsexpanded:stripped_cherry_wood_slab",
"slabsexpanded:stripped_dark_oak_wood_slab",
"slabsexpanded:stripped_mangrove_wood_slab",
"slabsexpanded:oak_leaves_slab",
"slabsexpanded:spruce_leaves_slab",
"slabsexpanded:birch_leaves_slab",
"slabsexpanded:jungle_leaves_slab",
"slabsexpanded:acacia_leaves_slab",
"slabsexpanded:cherry_leaves_slab",
"slabsexpanded:dark_oak_leaves_slab",
"slabsexpanded:mangrove_leaves_slab",
"slabsexpanded:azalea_leaves_slab",
"slabsexpanded:flowering_azalea_leaves_slab",
"slabsexpanded:chiseled_sandstone_slab",
"slabsexpanded:dirt_slab",
"slabsexpanded:coarse_dirt_slab",
"slabsexpanded:sand_slab",
"slabsexpanded:suspicious_sand_slab",
"slabsexpanded:red_sand_slab",
"slabsexpanded:gravel_slab",
"slabsexpanded:suspicious_gravel_slab",
"slabsexpanded:white_wool_slab",
"slabsexpanded:orange_wool_slab",
"slabsexpanded:magenta_wool_slab",
"slabsexpanded:light_blue_wool_slab",
"slabsexpanded:yellow_wool_slab",
"slabsexpanded:lime_wool_slab",
"slabsexpanded:pink_wool_slab",
"slabsexpanded:gray_wool_slab",
"slabsexpanded:light_gray_wool_slab",
"slabsexpanded:cyan_wool_slab",
"slabsexpanded:purple_wool_slab",
"slabsexpanded:blue_wool_slab",
"slabsexpanded:brown_wool_slab",
"slabsexpanded:green_wool_slab",
"slabsexpanded:red_wool_slab",
"slabsexpanded:black_wool_slab",
"slabsexpanded:obsidian_slab",
"slabsexpanded:snow_block_slab",
"slabsexpanded:note_block_slab",
"slabsexpanded:netherrack_slab",
"slabsexpanded:soul_soil_slab",
"slabsexpanded:packed_mud_slab",
"slabsexpanded:nether_gold_ore_slab",
"slabsexpanded:nether_quartz_ore_slab",
"slabsexpanded:podzol_slab",
"slabsexpanded:mycelium_slab",
"slabsexpanded:muddy_mangrove_roots_slab",
"slabsexpanded:chiseled_quartz_block_slab",
"slabsexpanded:cracked_deepslate_tiles_slab",
"slabsexpanded:deepslate_slab",
"slabsexpanded:dripstone_block_slab"

Craft slabs back into blocks

Works for slabs from this mod and vanilla slabs

This mod is still a work in progress and the especialy forge versions are not fully finished so please report any issues, bugs, and glitches you encounter.

This mod on modrinth