Doing my first primarily Melee/Pistoleer character and am looking for semi-realistic melee weapons! So it sparked my interest to see what your favorite modded or vanilla melee weapons are?

How realistic? From your character description I would assume you're going for light blades, so going for Chance's Knife early on in the game would be a good idea. You need a shovel though, you need to dig it up from his grave, which is near the marked location "Tribal Village" north of Goodsprings.

If you have Lonesome Road, the Bowie Knife and it's unique variant Blood-Nap have very good damage. High-ranking legionaries also carry the Machete Gladius, which is a kukri knife with good damage.

Millenia has done a few combat knives too. My character in my current playthrough actually has the Bayonet from the M1897 mod as the melee weapon.

Deathclaw Gauntlet for melee. If worst comes to worst then use the Shishkabob. Major damage.

Yeah, Millenia's Fairbairn's knife is very nice to use as it is quite aesthetically pleasing to look at.

Veronica and that power fist of hers pwnd everything

In vanilla FNV, probably the Oh, Baby!

Fist of North Rawr for its decent damage and it penetrates armor.

Vanilla Paladin Toaster and Oh, Baby! 
Lonesome Road Old Glory
Old World Blues Saturnite Fist super heated
Honest Hearts would be Salt-upon-wounds' power fist
Dead money idk

i just like when your repeatedly swing the sledge hammer it looks like you are gaining forward momentum XD.

I either use the super sledge or the combat knife. I like the super sledge but it can be a bit clunky to use outside of VATS because when you miss, you have to wait like a second or two to get another swing in. I can get sneak kills with the combat knife but it really isn't recommended for armored targets regardless because it sometimes won't kill 'em and they end up shooting at me and alerting their buddies if they are present. I used to use the Katana (GRA) but I am currently doing a play through without GRA weapons.

Also Balls companin mod has a God kinfe 946 dps and 286 dam. Too Op

for most cases I would say that you should buy GRA shishkabob at the gun runner's but that is a lot of money so save ye dimes and nickles.

In this category, my favorite weapons are the Bowie knife and Gehenna, to power fists somehow I'm not convinced

"knock-knock" and regular fire axe are my favourites

Yeah, I'd go for the Super Sledges and Fire Axe. If you're by any chance low on strength, Katana and Shishkebab would do you very nice as well.