5*'s tend to be pretty affordable, depending on who you want.
They're also available via the Roulette in the form of Premium and 4*+ tickets. They best time to cash those in is to wait until your pts at the bottom of the Roulette reach 0 and you get a x10.
TE come in 2 forms: TE(P) which are blue and TE which are brown. You can only trade TE, the brown ones. Same goes for Potion(P) - blue, and Potion - green.
Epona is rarely in demand and is best traded in to Leana's Exchange Shop for a chance at Edwin (5*). Anu, Danu, And Tartu vary in value, but usually between 1-3TE for a set of 5 depending.
Your units look to be quite common, and as such, won't get you much in the way of a trade until you max 5 of the 4*'s out to lvl 80. At that point, someone might give you 1-3TE for 5 of them as feeders.
Of your units, Arena, and Grex seem okay, while the rest are just ho-hum, even for 4*'s.
Look in the trading forum and see who is asking what for 5*'s. A good way to judge them is SPD, Deploy Cost, and then skills.