As a lefty
and a SIG owner, I trained myself to work the decocker with my trigger finger, just as I do the mag release. Now I only really shoot Glocks, so I'm certainly out of practice with my P220, but the technique worked. I don't use the slide stop (AKA slide release) on any pistols and prefer to "slingshot" the slide, so that's a non-issue for me. I think the most difficult handguns for most lefties to operate well are DA revolvers like S&Ws and Colts. As much as I love my S&Ws, it can take a while for some lefties to find a reloading technique that works for them. With a classic SA revolver like a Colt SAA, we lefties are at no disadvantage when it comes time to reload.
All AR-15s are very lefty
friendly, with the possible exception of early models that lack shell deflectors. Even those work fine once you've upgraded the extractors: then they will usually eject at about 1 or 2 o'clock and the shell deflector is more or less superfluous. It's slowly becoming a matter of some contention for me, but lefties who feel they need a "left-handed" AR are beginning to grate my nerves a little.
If you want
one because it makes you feel better, then by all means buy what whatever you like; but no one will ever convince me they're necessary. I've been shooting standard-configuration ARs for about 20 years, and find them to be one of the most lefty
-friendly platforms around. The only possible addition would be an ambi safety selector, but even that I can live without.
I absolutely HATE shooting righthanded bolt-actions, but have had to learn to deal with it, mostly from my love of surplus rifles. If I were investing in a newer bolt-action sporting rifle or target rifle, I would never in a million years buy a righthanded action.
Off the top of my head, I would add to your list:
M1 Carbine and M1 Garand.
Most lever actions, but especially the Savage 99 and the Winchester 92. Some other designs do chuck the brass out the right side and it may whack you from time to time, but that's not really a big deal. Most reload via the right side, which works well for us lefties.
Ithaca 37 shotgun - bottom feed and eject, great for a lefty
. Most pump-actions work okay for me, though; but I do like the Mossberg's safety the best.
Most (if not all) single-shot, falling-block rifles. I haven't fired many of these but they all worked fine for a lefty
I'm sure there are more, but I just got up. I'll probably add more when my brain is working a bit better.