Gay representation:

His strong female characters:

Invisible Girl/Woman (both in terms of her powers and personality) and She-Hulk come immediately to mind.

Black characters:

Too many to even mention (at least more than I can get into this late at night)

Many other marginalized groups:

Again, too many for me to get into this late at night.

Puck, Box, Uncle Jake, wheelchair users such as the construction supervisor working on the rebuilding the Baxter Building and the secretary at Dollar Comics in Next Men.

This is without racking my brain or going through my TPBs and long boxes.