MOST IMPORTANTLY: DON'T BUILD BOOTS!!!
Almost every champion's most viable runes are Dark Harvest/Hail of Blades, Ravenous Hunter, Transcendence and Gathering Storm. If you aren't taking these you might as well be inting. Unless otherwise specified, this is your rune setup for everyone (if they auto alot, Hail of Blades, if not, Dark Harvest).
All champs are listed in order within each tier.
If you find some wonky build that just works for any of the lower tiers, lemme know so I can see for myself and update this.
Edit: Many of the ADC's or other champions that build crit have had their URF performance drastically altered in some cases. Updating their placement is a WIP.