Guano redstone has the lapis tag:

Some suggestions

• All the eggs lack the forge:eggs tag, and the minecraft:eggs tag doesn't exist by default. Would be nice if they had the forge tag so recipes could easily use them (not sure if this was intentional, so i wanted to mention it just in case it wasn't).
• Items tagged with forge:coins/iron, forge:gears/iron, forge:dusts/iron, forge:plates/iron, forge:rods/iron, and forge:nuggets/iron should get the ferromagnetic tag (also applies to Steel and Netherite. Any Cobalt items with these tag variations should receive the ferromagnetic tag as well).
• Quark's various Raw Iron blocks should have the block and item version of the ferromagnetic tag

Mod support

I'm not sure how in-depth you want to go for mod support (I'd personally say as much as possible - at least for the ferromagnetic tag and a few others), but I got a short list of mods that could use the various custom tags this uses:

Ferromagnetic

• Outer End's various Cobalt blocks & items
• Regions Unexplored's Cobalt Obsidian

Gloomoth/Underzealot

It seems like the Underzealot only targets torches (or anything with 14+ light level), but if these could at least have the Gloomoth tag it'd be nice

• Buzzier Bees (Honey Lamp)
• Deeper Caves' various lamps & lanterns
• Galosphere's various lamps
• Phantasm's Purpur Lamp
• Outer End's various lamps (and all the Cobalt stuff having the ferromagnetic tag would be nice too)
• XyCraft: World's torches & lamps
• Quark's various lamps & lanterns
• Regions Unexplored's Hyacinth Lamp
• Upgrade Aquatic's various torches, lamps, and lanterns

I added an extra comment to the first issue I made as well, but just in case you didn't see it I'll paste it here:

The Magnetic Levitation Rail doesn't have the minecraft:rails tag

And the Magnetic Light and Froglight from this mod don't have the Gloomoth block tag.