Category of the fics you won't beta: I prefer not to beta het or first person POV. I won't beta death-fics or Rodney-bashing fics. I'm not opposed to non-con, but I don't like full on rape. Having said that, I'm okay with it depending on plot, circumstances etc. No BDSM fics either.
Pairing of the fics you'd beta: I'm big on McShep, love Carson/Radek, but I'm open to most slash pairings, including femslash.
Pairing of the fics you won't beta: No OC-centric fics. I don't like pairing John and Rodney with anyone but each other, unless they end up together in the end.
If not pairing oriented, character fics you'd beta: I love Rodney-centric fics and I'm partial to Rodney-whump.
If not pairing oriented, character fics you won't beta: Dr. Keller-centric.
Type of beta you'd do: Whatever the author asks really. Grammar, spelling etc. If someone asks me for opinions on a particular piece, if it works, needs adding to, that kind of thing, I'll happily give that too.
Length of the fics you'd beta: Any length