Your Bunny Ear Cactus is Opuntia microdasys.
Hard to say on your "Light Bulb", but check out Mammillaria parkinsonii to see how it compares.
Your unlabeled dollar find looks like a type of Ferocactus to me. Maybe better to ID it when it grows a bit.
I think someone gave a common name of Domino to your Echinopsis subdenudata. I do not believe it is a cultivar (no different from the species), but is being circulated as such (sort of a good descriptor for it).
I'm curious to see your Mammillaria mystax when it flowers, to confirm that ID.

Thank you Rose... I will keep he post updated when & IF it ever blooms....LOL

I believe that the $1:00 find is a small

Ferocactus emoryi

Update, I think the $1:00 one is actually Ferocactus latispinus. There's a picture on the Lowes cactus supplier's website: https://altmanplants.com/plant-shop/ferocactus-latispinus-fish-hook-cactus/