You've got all auto's.
Another auto doesn't do much for you. You've already basically got whatever it would be you would buy as another auto.
But a revolver opens up a different type shooting - and if 357/38 Special - different cartridges - interchangeability - versatility.
There are many good ones out there. Smiths and Colts are classics; Rugers are very well made. A Ruger SP101 or an Sp100 are excellent guns that both can be had in 357. You can even find a 357 with a 9mm interchangeable cylinder. Now there is some versatility!
But another thing I don't see on your list of present guns is a small concealable - like maybe a 380. I know, I know - chit chat, chit chat - not enough power, not enough power. Just don't stand in front of one! The small ones make extremely versatile conceal guns, if you are into concealed carry - and legal.
Myself - I have a similar collection - auto's, larger and smaller calibers, revolvers - and I do favor revolvers for their reliability under stress. But, much as I prefer the revolvers or even a small 9mm, my Ruger 380 is the almost always go to gun for concealment -- for me. It just works - and the others ... I choose not to take - because I don't feel like hassling with the size, and holsters, and inside/outside waistband - driving discomfort - bending ... on and on...
The little LCP goes in my back pock in a leather backpocket holster - in virtually any clothes - dress slacks for fancy affairs, jeans, work clothes, bicycling, ... It's always there.
To shoot it - it packs a wallop - no joke. After all, it is light. And, it is not a pleasant range gun to pass some pleasant time with. But that is not what it was designed for - people seem to confuse that fact - it is a personal protection gun that you can conceal easily - that is it's purpose - not pleasant shooting. If you want a pleasant gun for the range get a large something - heavy - in a 9mm - very pleasant. If you want to be brave go to a long barrel 44 mag - but be prepared. The 40 cal's are a little snappy so get a heavier one, ... for pleasant range fun.
But that's not what the LCP is designed for, or about - fun at the range. I have certainly learned that. It is designed so that you are armed.
It has never misfired. And it is always with me. And that makes a big difference.