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.

Arum maculatum, our native wild arum. (I seem to recall you are in the UK). Not unattractive but can spread about. Always an early riser in the Spring. http://wildflowerfinder.org.uk/Flowers/L/LordsAndLadies/LordsAndLadies.htm

Just went out and smelled a plantaginea flower. Might have to cut this scape and bring it inside. I planted this right outside my bedroom window, but it's still too hot to open up the house. Guess I didn't think that one through... It does make me glad that plantaginea is such a good grower! I've got propagation on the brain.

This means that an ebayer sold me carnosa with a pubicalyx label. Not this one but I got one some months ago and It looks just like this but darker but its OK it was only $5