I'm assuming by Early game you mean before chapter 10 or something?
If so, Tiki's geosphere is great on units that will usually end up adjacent to someone like a staff users/ki adept like Framme.
Lineage from the 3 houses bracelet can help you grow units faster.
If after Chapter 10, brave assist from Lucina on your backup units is good, more chances for chain attacks without positioning. Alacrity on your naturally speedy units like ChloƩ, Lapis or Kagetsu can help a ton for safe one rounding. You could also inherit the cheap +spd skills on your somewhat slower units to help them hit speed benchmarks.
Vantage from Leif can work on frontliners on enemy phase.
While not a skill itself getting the Mercurius weapon from Marth as soon as possible can really pay off in the early game. As its basically a paragon sword.