You can search for businesses that accept Suica but it's in Japanese only.

I did a quick search around Aoyama Itchome station but there aren't many eateries that accept suica. Looks like there is an Italian restaurant called La Pausa in the Aoyama Twin Buidling. In the same shopping center, there's also a Subway. Diagonally across the Aoyama 1 traffic light on the northwest corner is is a St. Marc Cafe.

If you go to a bigger station, such as Shinjuku, you can find many chain restaurants that accept Suica: Izakayas (Japanese pubs) Nijyu-maru and Sakura Suisan, gyudon (beef bowl) restaurant Matsuya, etc. There are tons of choices.

If you still have balance leftover, many shops and restaurants in NRT take Suica.

Edit:
Missed the part about Roppongi in the OP.

There are 5 restaurants near the Roppongi station:
Tsukiji Gindako near the Roppongi intersection. They sell takoyaki (octopus ball) snacks.
Tsubaki Cafe near exit 1a/1b of Hibiya line part of Roppongi Station.
Nijyu-Maru izakaya 1 light southeast of Roppongi station/intersection on Gaien higashi dori. It's across from Don Quixote store.
2 Le Connaisseur cigar bars.