• #minecraft:saplings item tag is missing the blossom tree saplings
• #minecraft:leaves item tag is missing the blossom tree leaves
• #forge:chests/wooden, #forge:chests, and #forge:chests/trapped item tags are missing the new oak chests
• The block tag versions of the above tags are missing all wood variant chests
• #minecraft:flower_pots block tag is missing the quark potted plants (including glowshroom, blossom saplings, and the 13 new ones)
• #forge:sandstone block and item tags are missing soul sandstones
• #forge:sand block and item tags are missing soul sand (could be intentional)
• #forge:sand block tag is missing gravisand, despite being included in the item tag. (Vazkii: gravisand shouldn't be in #forge:sand)
• #minecraft:sand block and item tags are missing soul sand and gravisand (could be intentional)
• #minecraft:wooden_slabs block and item tags are missing colored plank slabs
• #minecraft:planks block and item tags are missing vertical colored planks
• #minecraft:walls block and item tags include paper walls (could be intentional)
• #forge:mushrooms item tag is missing glowshrooms
• #minecraft:enderman_holdable block tag is missing glowshrooms and glowcelium (vanilla mushrooms and mycelium are included in Vanilla)
• #forge:stone block and item tags are missing the custom stones and variants. (Also missing all variants other than polished of Vanilla stones)

That should be a fairly comprehensive list. I'll edit this if I find any more.

Thank you for the list. I crossed out any intended ones for future reference. I'll have it fixed for the next update.

Can I ask why specifically vertical colored planks aren't included in #minecraft:planks, while vertical planks and colored planks are? Thank you for the quick reponse!

The 3 new chest types are missing from the #forge:chests and #forge:chests/trapped block and item tags.