Aliasing logan → logan_(disambiguation)
Link to alias

Reason:

13 logan_(* tags. Other tags start with Logan.

1) 2 logan_(artist) artist
2) 1 logan_(autumnsunrise) character
3) 7 logan_(awkward-sloth) character
4) 8 logan_(bgn) character
5) 1 logan_(character) character
6) 2 logan_(fenfenftw) character
7) 1 logan_(film) copyright
8) 13 logan_(fox) character
9) 1 logan_(geckoguy123456789) character
10) 8 logan_(pit_fighters) character
11) 1 logan_(qwerty-0) character
12) 4 logan_(silverboltbw) character
13) 8 logan_(teer) character

Plus a bunch more at
https://e621.net/tag?name=logan*&type=&order=name

related:
I started this alias suggestion because wasn't sure what tag to use for Marvel character Wolverine aka Logan.
1) one (with the character) tagged with just Logan : logan -wolverine_(marvel)
2) approx 17 (with the character) tagged with just wolverine_(marvel) : wolverine_(marvel) -logan
3) 15 are tagged with both Logan and wolverine_(marvel) : wolverine_(marvel) logan

wolverine_(marvel) will probably work until someone uploads art depicting Laura Kinney (aka X-23) as Wolverine (Laura was Wolverine from 2015 to 2018)
https://en.wikipedia.org/wiki/X-23

Currently Laura's e621 tag is x-23.

If Wolverine Laura gets uploaded to e621,
then tag of Logan_(marvel) might work (for the male Wolverine).
There are other Marvel characters with Logan in their names, but none seem to have Logan as a first name. Unlikely any of the others will get uploaded to e621 (unless in a group image).