The Angler - Plenty of interesting applications of this guy’s abilities. One of the most obvious combos is with Christine Perfect, letting you hit Q-value Dudes (particularly nice against Anarchists, with their wimpy and starting-popular Dudes in Stevie Lyndon and Tayari), and Sanatorium letting you hit 8s (or Ks with both used together).
DMH decks might be particularly suited to running him (even off-value), since they’ll combine heavy shooting power with the option of using his second ability to reset his value to every primary value of opposing DMH decks.
Furthermore, the fact that values ‘bottom out’ at A lets Christine Perfect set up any Dude of value 6 or less for a callout by an A value-Angler (Of course, this requires this low-value dude to fit Christine’s “highest grit” requirement, but this will happen sometimes - either because the whole deck is low-value or because of heavy losses.)
Also also, DMH decks will frequently pack one or more Pedros (and occasionally Rapiers as well), which offer you even more opportunities to tailor his value for specific targeting.
And of course, his value-resetting can also be used completely independently of his callout ability, just to buff him against Shotgun/Puppet/whatever, or to manipulate who an opposing Mason Adler can target.