Bully club you want Thrust (more damage on heavy melee charge), Haymaker (helps killing horde), skullbreaker (more damage on stagger) and momentum (more toughness regen on melee hit) is somewhat neat. Shovel needs Brutal momentum and Thrust.
All bully clubs and shovel, special attack - uppercut punch has really high stagger value. You can practically keep staggering or lock down monstrosities with Heavy into Special and repeat on their weakpoint (head). Daemonhost you need to aim higher over the head and Nurgle Beast, the giant yellow spot on the back. Different timing for each monstrosity.
Knife 3, you don't really much melee talents. So it pairs well with heavy stubbers and getting that big boom grenade. Which you only need gun lugger active ability and then go for middle tree for easy defensive bonus talents.
Most of gunlugger talents are very meh, you probably need active ability with flame augment, more explosion radius and more ammo reserve. So if you don't use knife 3 (because this combo is bad against armour targets) you can still go for for melee talents for bully clubs.
Just harder to play with, because you'll missing bleeding from heavy melee attacks (more melee damage and damage resistance from bleed).
Range options, beside Kickback, Rumbler and Gorgon stubber.
Grenade gaunlet is outclassed by Kickback, more ammo reserve but reload speed is too slow for its magazine size. Kickback constant reload has better dps overall with Adhersive charge (sticking to ogryns and monstrosities).
Melee from gaunlet is counted as heavy, you'll still somehow infect bleed to enemies if spec into bleed from heavy melee attack. However, it isn't a melee weapons, you don't get any toughness regen nor damage boost from its melee attack.
The special attack punch into explosion is okay for horde. Even with all damage bonus to Carapace, it still needs like 3 shot to kill a Crusher. So nearly an entire mag rather than whole mag, sad.
Ripper guns, all must have Can Opener blessing (gives you rending on attack). So you can give yourself some melee damage boost by shooting or stabbing at Mauler, Crusher first. Or you can decide to waste a whole mag on them to kill a Crusher at more some range.
Ripper Mk2, easy to use, like normal shotgun. Mk5 (my choice) has lot more (highest) recoil, but much tighter spread, which unironically pretty good at killing sniper. Mk6 (brown) when bracing has much wider spread, so really good against horde.
Ripper guns have pretty fast swap and reload speed for all considered.
Kickback and Gorgon stubber (even other stubbers to certain extend) are very good at killing monstrosity with gun lugger ability activated. I pretty much only use stubber to that specific cases with Knife 3, or club.
Stubbers aren't really great at killing carapace.