From my experience: Camo, Jetpack and Hologram are probably the three armor abilities I see the most. Thruster Pack, Hardlight and Promethean vision are the second most common set. Auto Sentry and Regen Field I see once in a blue moon.
Frags and Plasmas nades get seen much more often than Pulse. Can't put into perspective which of those two I see more often since I remember the incidences of being stuck by suicide throwers more than generic blast radius kills.
DMR and Assault Rifle are definitely the most common loadout primaries I see. People using BRs, Light Rifles or Carbines, based on what people have said on this board, are usually doing so out of personal preference or because they've already done the DMR commendation and want something else to work on. Boltshot's getting less common from what I've seen.
For Infinity Slayer, I usually end up on Haven (primarily), then Adrift and Solace. Complex hasn't been seeing much love. I don't play big team slayer, but iirc there were one or two maps that get voted for virtually all the time. --- You can't call him out for being wrong when he never intended to be right - Stephen Colbert "Bad Mojo" is not a diagnosis - Dr. Foreman, House, M.D.