I feel like the white Citizen and Seikos serve the exact same purpose. They even both have day/dates and the same style indices. Pick which one you like the most and sell the other.
The black dialed Citizen/Bulova pair are the same story. I'm sure you favor one over the other-why have both? It looks like both of these sets are combining auto/quartz movements. If that's the case, then I guess I understand. Maybe have one black/one white, and one of those be quartz/one auto?
The black dialed divers with crowns at 4/8? Same story, except both of them are automatic. Are you a lefty or not? If you bought that Citizen I'm going to guess yes, so I would keep that one and sell the Seiko. It's already very similar to your GMT.
Speaking of the GMT, area you really satisfied with it? There are a lot of examples from the Seiko 5 lineup here, and I feel like this is one that is prime for an upgrade. I like the 5KX series, but personally I'm not a fan of the GMTs. It's not a bad watch, so if you like it and don't want to spend the money to upgrade, I completely understand.
I don't see a reason to have two G-Shocks, unless you're just really that indecisive about analog v digital, or a big fan of them so much that you want to collect all the styles. Personally, I'm a bigger fan of square G-Shocks than the Casioaks, so I'd ditch that one. Plus the square one looks like one of the pricier ones with a dot matrix display. I have one G-Shock-the square 5610U, and it's one of my favorites in my collection, but I don't want another one. But you do you.
Seiko 5 field watch and Flightmaster? Those are fucking cool, hold onto them. I can't even tell what brand that other chrono is, but it's a very nice looking rip-off of the omega moon watch, so if it's actually good, hold onto it I too guess.
None of these look like particularly bad watches, but you have a lot of overlap. You look like you may still be trying to figure out where your preferences lie. I think it's time to take a hard look at this collection, figure out what those are, and maybe consolidate and/or elevate the quality on some of them.
This is incredible. I'm seriously considering this watch (even though I've never paid more than $1000 for a watch), and now I'm seriously considering a felt strap for it.