If you like tetras I used to keep a school of columbian tetras with my EBAs and they got on well and looked cool together.
You might get away with a small group of Bolivian Rams or orange head geos but I personally wouldn't go for the geos in a 55G but would consider 3 or 4 of the Rams.
If you want something unusual maybe some upside down catfish or pictus cats would suit the set up too.
Also I'd keep an eye on the angel and barbs together, it's a combination that really shouldn't work but you may get lucky. Adding another angel would be nice for your existing ones as Angels really are a schooling fish too.