Reaper:
-Two Summer Games items

Tracer:
-One Summer Games item
-One EVENT_8 item

Mercy:
-One non-event item
-Two Summer Games items

Hanzo:
-Two Summer Games items
-One EVENT_8 item

Torbjorn:
-One Summer Games item

Reinhardt:
-One Summer Games item
-One EVENT_8 item

Pharah:
-Two Summer Games items

Winston:
-One Summer Games item

Widowmaker:
-Two Summer Games items

Bastion:
-One Summer Games item
-One EVENT_8 item

Symmetra:
-One Summer Games item
-One EVENT_8 item

Zenyatta:
-One Summer Games item

Genji:
-One Summer Games item
-One EVENT_8 item

Roadhog:
-One Summer Games item

McCree:
-Two Summer Games items
-One EVENT_8 item

Junkrat:
-Two Summer Games items
-One EVENT_8 item

Zarya:
-Two Summer Games items

Soldier 76:
-Two Summer Games items
-One EVENT_8 item

Lucio:
-Two Summer Games items

D.VA:
-One Summer Games item
-One EVENT_8 item

Mei:
-One Summer Games item

Sombra:
-Four Summer Games items
-One EVENT_8 item (Note: there is an additional item listed here as "Hero Metadata" instead of "Cosmetic". I don't know what this is.)

Ana:
-Three Summer Games items

Orisa:
-One non-event item
-Four Summer Games items

Achievement Rewards:
-Eight new items (one of these is likely a player icon for logging in, and thus isn't tied to an achievement)

Summer Games (not tied to any hero):
-One new player icon