Here I will add builds that I have tested and found good.
Updated: 4th of July 2016 - Medivh update.

E.T.C.
Tier 1: Block / Prog Rock depending on enemy team.
Tier 5: Groupies / Show Stopper depending on enemy team.

Li-Ming
Tier 1: Astral Presence / Power Hungry depending which one you like more.
Tier 2: If you don't need health from kills ( Dominance) take Triumvirate.
Tier 7: Temporal Flux / Tal Rasha's Elements depending do you need slow for team kills or more damage.

Rehgar ~ For shield & damage build.
Tier 1: Electric Charge
Tier 2: Feral Heart
Tier 3: Blood and Thunder
Tier 4: Bloodlust / Ancestral Healing depending if you need damage or massive health.
Tier 5: Earth Shield
Tier 6: Rising Storm
Tier 7: Gladiator's War Shout / Rewind depending which Heroic you took.

Valla ~ If enemy has high CC like E.T.C. consider changing:
Tier 4: Strafe for Rain of Vengeance (heroic)
Tier 5: Frost Shot for Giant Killer
Tier 7: Nexus Frenzy for Bolt of the Storm