Sorry about dragging you out of character. My suggestions might be more helpful in that regard if I knew more about your character than:
Tiefling Warlock, fey pact.
Cha 18, con 14, int 16, wis 13, dex 10, str 8.
I'm sorry if I come across as snarky, but I'm feeling a little put upon because you started with "there's no feats", then, upon being shown one changed to "not enough feats", then, when shown several changed to "not enough feats that are in character". Having the bar repeatedly raised on me kind of gets my goat.
Edited for grammar.
There's no feats that do Warlock stuff. Weapon proficiency: Bastard Sword is not an example of a feat that meets any criteria. No one shifted the bar. No feats and not enough feats never included Alertness. I dont care about Alertness. What makes you think its a Warlock feat? It isnt. Warlocks are Strikers. That means they hurt people.
Rogues can take back stabber, two weapon fighting, weapon focus, and 12 more feats to hit people harder, without any of those requiring cha 13, or con 13 or wis 13 or int 13.
Reading out fighter feats from the book doesnt answer the OP, it essentially just threadcraps. "No warlock feats?? Why not use a Bastard Sword with your 8 str!"