Three nice tetra i have worth looking into are:
morse code tetra (nice clear/orange - similar behavior for ember but look nicer in a tannis environment)
Trochilocharax ornatus - these are a clear tetra with colour accent and buzz around like humming birds shoaling. The ones i have are really small
and
Hyphessobrycon eilyos - these are very unique and extremely greedy eaters - they seem to range from pure black to silvery/grey (not sure if mood/sexual dimorphism or whatever). They are a very busy tetra much like emerald eye rasbora and love to swim (the morse code is similar to ember in that it sits still and look pretty).
One day when i get tired of playing with my rams i might try to breed the eilyos as they are kind of pricey and if i want a larger school it would be cheaper to make my own. In the right kind of aquarium they are truly stunning and unique. The ornatus are very different - they stay near the top and as a group make a very busy body buzzing around but are really quite small - maybe too small for your lats esp if yours hang near the top like mine (i have the ornatus with the elizabeth who are very polite and gentle to their tank mates having a ladies name).
And if you want pencil fish there are marilyn and margituas or the pricey epesi all three are very much worth having esp in a densely planted aquarium as i have a problem keeping plants from growing in blackwater environment so i end up with a lot of dense plants.
If you have them in a larger aquarium like 55 or 500 there is the interesting Hemigrammus rubrostriatus - i picked up a large group of these in hope that my geo would leave them alone (one of my rummy got scared and swam into an open geo mouth). They are rather pretty but otherwise quite boring.
