As a collector who limits himself to Batman and Batman related characters, fun comic-accurate variants are my favorite Pops by far. With several of my most wanted figures checked off the list now (Bullseye, Zebra, Rainbow, and the still elusive Zur en Arrh - and from our original list, Jungle Batman, Negative Batman, and the Detective 165 suits!), I thought it might be fun to come up with some new suggestions for Funko to pursue on the Batman front.
For those sick of Batman Pops, I apologize in advance!
My picks:
The kilted Dark Knight!

Batman in a suit!

Batman Machine:

Scuba Batman:

The original Thomas Wayne Batman:

Batman robot twin:

Culturally insensitive Batman:

Fireman Batman:

Knight Batman:

Rip Van Batman:

Batman II:

Alien Batman:

Another alien Batman:

Captured by aliens Batman:

Bat-Baby:

Batman Creature:

Bat-Hulk!

Batman X (Dr. Double X Batman clone):

Batman Genie:

Mummy Batman:

Composite Superman is another huge want (and one I'd put money on Funko actually making), even if it's not actually Batman in the costume:

As far as Elseworlds go, Batman Holy Terror would be a fun one:

And another personal favorite, The Blue, the Gray, and the Bat:

Now that Red Rain Batman is on his way, how about a Frankenstein Batman?

That brings us to the mid 90s and Azrael Batman:

Version 2 of AzBats:

Troika Batman who briefly lost the underwear:

DC One Million Batman was pretty great:

Dark Knight of the Round Table Elseworlds Batman:

(Update! Red Son Batman now on the way!)
Green Lantern Batman (both from the regular comics and the In Darkest Night Elseworlds:


The version of Sinestro Corps Batman that hasn't been made yet (we now have the yellow/black costume!)

As well as Batman 666:

And don't forget the Batman, Inc. look which I loved:

And Dick Grayson as Batman:

And for recent suits, Zero Year could be really interesting:

Or the Zero Year survival look:

And Bruce Wayne from Earth Two:

Then there's Dick Grayson from Earth Two:

And Batman 3000:

And the two looks Commissioner Gordon had when he wore the bat-suit for a bit:

As well as Batman's current look in Rebirth:

The evil Batmen from DC Metal! (So far, we're getting the Dawnbreaker Batman (Batman/Green Lantern) and the Man Who Laughs (Joker/Batman). And now we can cross Red Death (Batman/Flash), Batman the Merciless (Batman/Ares), and Batman the Devastator (Batman/Doomsday) off the list!

Not to mention, Batman's new look in Doomsday Clock:

And there are some comic-accurate armors as well.
Like, the Hellbat:

The Justice Buster:

The Thrasher:

And when Batman used Clayface as armor:

Now let's talk TV and movies.
The Batman (1943 serial):

Batman ane Robin (1949 serial):

And now that Batman '89 is finally coming, let's get a Batman Returns Batman, complete with stylized chest armor and bat-symbol:

Batman Forever, Version 2:

And Batman and Robin:

(The Batman & Robin version two suit is now on its way!)
Some options from The New Batman Adventures:

Justice League Unlimited Batman:

The Batman:

Batman: The Brave and the Bold:

Beware the Batman:

Young Justice Batman:

Justice League Action Batman:

Teen Titans Go Batman:
Lego Batman! (Not sure how this would work as a Pop...):

And then there are some video games, like...
Arkham City (only slightly different from the Arkham Asylum version released):

Arkham Origins

Injustice:

(There are some from Injustice 2, but kind of too many possible variants to count...)
Many more Batmen where this list came from! Here's hoping Funko gets to all of them one day!