Some nice heroes are gem roll only (or special event only), but a nice little team can be had with just shards.
Cleric - team heal and boost.
Sun Maiden - to stab the biggest foes. Will hit damage caps at even skill one, but higher skills curb enemy attacks.
Set - gather all of the enemy in one spot and stun then all.
Serq - asks the enemy why they're hitting themselves.
Marid - Clears out entire dungeons with a single proc.
Suriel - Holds the Revite 5 for the entire team, or two teams for lost realm boss fights.
Doomrider - Stands toe to toe with the toughest foes.