Finally found adult/large snails without shells; various shapes and skin textures; different species

You may notice two different skin textures on the baby/tiny snails without shells, from which the adults/large ones I've found have different skin texture and body shape altogether. They might belong to three different (sub)species.
Google lens matched the big ones to Spanish Slugs or Red Slugs, while the little ones could be some kinds of greenhouse slugs or limaxes (not sure this is how the plural is spelled). Some of the little ones might actually be adults, but of a much smaller species than the brown and the red/orange/brick-like colored ones. I'll look some more when I have a bit of time.