All of the above..
College(unlike pros are usually fully exposed and not just misfiring) teams stuck on 0 or 3 at halftime, with no offensive push generally stay on 0 & 3(I.E. lose 2nd halves)..if fair 2nd half lines set on high action games that require tight linemaking at half, especially if in rivalry games where letting up isn't much of an option for the frontrunner.
1 pt home favs are usually false favs if they are the public team or perceived better team, and especially when big isolated tv game, and line often is saying something if large public consensus..yet doesn't creep up.
Love road dog in NFL intra-conference games, when visting team is an isolated or largest viewing audience game while being televised on their own conference's tv network.
Somewhere between the last two weeks of November and the first week of December is a week where the dogs go about 13-3, with most winning outright on the ML
USC, Mich, Mich St, and BC vs.ND..until recently always outright dogs
Ala outright or ATS when at LSU, UF outright or ATS vs UGa
OU over Texas in MB era
Miami in Sunshine tilts vs FSU and UF anywhere
Peach & Holiday Bowl Dogs..actually most all dogs pre-New Year's day Bowls
#2 outright over #1 in NCAA title tilt
Getting points vs. Titans or Eagles in playoffs
College home tv dogs vs 2nd or 3rd week straight roadies..especially if deflated in big game loss week ago and now at hungry middle-of-packer
etc..
Every year is different, and things change, but certain spots have numbers tough to buck.