>Killzone
Pretty average series that has some good lore and ideas, but overall middling and linear gameplay and level design, multiplayer was pretty good back then though. Mercenary is also pretty damn good especially for being a handheld spinoff.
>Resistance
Underrated series. First game played a lot like Halo 1 and 2 but better, with a good atmosphere, level design, and solid multiplayer. 2's campaign was a bit disjointed and not as good with its more linear levels and cheap difficulty spikes, though the multiplayer was really good for what it was despite being way different from the first. 3 had a better campaign than 2 and I thought it was really novel how the start of the game takes place in my home state but the multiplayer was a disappointing CoD-wannabe.
>Disruptor (not a Soyny FPS technically but I'm including it anyway)
Great Doom clone that deserves a Doom 64 EX-type sourceport.
>MAG
A neat, ambitious game that I think would have really taken off… if it had been released for PC.
>SOCOM
Pretty good tactical shooter series on the PS2, online multiplayer was also probably the best for the console, really a shame the series lost focus and died on the PS3.
>Syphon Filter
I don't really count it, has more in common with Tomb Raider and Metal Gear Solid than a normal shooter. Good games though.
>Warhawk/Starhawk
RIP, Warhawk was a really fun game that I'd still be playing if they had made it to PC. Starhawk was okay but not quite up to par with Warhawk imo.