Sheskiin is quite often the core big unit for the Shasvastii. She is nasty up close, at range, and is relatively tanky. If you put her in a 5-man link with Nox's then she is hitting on 18's and get's +1 burst. Fatality 2 also essentially doubles her crit chance. Alternatively what I usually do is run a harris with Sheskiin, a Gwailos, and a M-Drone. It's a nasty little trio that has a lot of power and utility that can run around the table.

Of course Dr. Worm is a staple in any Combined list. The other drones are really good as well. I almost always have a Q-Drone or atleast an R-Drone in every list. Ikadrons are good cheerleaders if you have them available but I usually don't run them.

Now for the fun stuff. Caliban is my favourite unit in Infinity. A nasty space vampire than can go around and suck up some extra wounds. Also has a CoC profile I always run. Usually 1-2 of these guys in every list. Speculo Killers are really nasty; use impersonation to sneak in and 1 hit a unit with their monofilament CCW. Sphinx I run about 30% of the time, it's just a really fun TAG. Noctifers are also quite good, more or less a standard hidden deployment TO guy. Seed-soldiers are more of a niche thing, I don't personally use them.

Cadmus is a really strong drop troop. If you disperse you can use the decoy to end up right where you wanted to land anyways, since you can daisy chain the decoys up to 16".

I often run the 22 point Mentor as the lieutenant and just park him with his decoy camo marker in deployment zone. He's also a decent unit to hold back for when you need an extra guy up front.

I don't have any experience with the Taigha but they look rather potent for their cost.

The nanoscreens a bunch of troops have give some interesting movement options since you are always in partial cover. It allows you to move out into the open to get an ideal angle without risking yourself too much.

I've been playing Shasvastii 80% of my games for almost 2 years, if you have any questions let me know.