This is my first post so I have no idea what I'm doing with regards to formatting. Feel free to correct me or even copy this and fix the formatting yourselves (make it neater/clearer or whatever).
I'm gonna copy paste a bunch of research that was done for Rome II Total War Iberian mod that I believe will be very useful to you:
A note on tribes:
The Lusitani (because of Viriatus) and the Arevaci (Celtiberi, because of the defence of Numantia) are probably the most iconic (let's say well-known) tribes, along with the Cantabrians (because of the Cantabrian wars in the later times of Augustus), but I don't agree they are the more unique.
All the Lusitani, the Celtiberi and probably the Cantabrians too, were either celts or heavily influenced by celts, so they might be similar to an extent to gauls.
I'd say the more unique cultures were the Turdetani (because of the Tartessian Heritage) and the iberians (which were influenced by external cultures, like the phoenicians or the Greeks, but retained their original "feel"). Visually they are quite more unique too (although, again, they will probably be present in the carthaginian roster).
The Vascones were very isolated and part of the distinct Aquitanian culture, so they might be quite unique too (though i'm just guessing here, i have seen very few archaeological evidence of the actual "looks" of the northern tribes).
The only peoples that were not of indo-european culture in Hispania were the Aquitanians, the Iberians and those of Tartessian heritage (mainly the Turdetanians, although they are often included in the iberian group).
Also, those tribes that were more influenced by Greeks bring some interesting options to explore. I always liked this drawing of an Ilergete from the present-day catalonia (i don't know to what extent it is historical, but the greek influences from the nearby Greek colonies of Rhodes and Emporion bring many interesting design options, like iberians with corinthian helmets).
A note on falcatas:
The falcata, it was mainly used in the iberian (south and levant coasts) zone, and to some extent, by the celtiberians, but not by the celts (check the spoiler below). So, again, nothing to do with the Lusitanians (which were heavily celticized). As for the triangular-shaped dagger, I'm not entirely sure but i believe its the same.
Numantian Helmets (very cool):
The warriors of the different tribes:
Turdetanian (present day Andalucia):
Edetanian (present day Valencia):
Note the scale armour and heavy cavalry
Also based on that vase, some people have assumed they used body painting/tattooing (?) (check the black drawings in legs and arms), but I doubt there is actually any real reference for that other than the vase, it could be any kind of ornamental piece. In the other hand, I seem to recall reading somewhere that that vase depicted warriors in ceremonial garments, so body paint could make sense if it's any kind of ritual.
Celtiberians (present day castille): These people, as the name implies, were a cross of iberian and celtic influences:
There is much more in depth knowledge of iberian tribes in the full post:
total war preview
If you want to know more, I suggest this other Rome II total war mod post which has loads of pictures of the units they made, they also look pretty great:
Full thread:
total war