I don't know about Gambit fanfic, I haven't read Xmen fanfic or Gambit specific in some time. I do read fanfic but in a totally different fandom.
Gambit is in general slashed with any male character the writer likes the most. There are a few romy fics too and I don't read those either.
What's missing is more action/adventure stuff. Maybe another guildmate would have some suggestions.
AO3 (archive of our own) has a tagging system, and filters so that you can be specific in what you want to read. For example, you can include Gambit then hit filter and only fics with him in it shows up.
Fanfiction.net, you'll have to hope the people writing gives enough info in their summaries.