Blitzcrank
His rocket grab is always firing his right hand, which makes the skillshot have a slight angle across his body; also only the hand part of the animation has the hitbox. Which means with patience & practice, you can pull someone from the opposite side of a moving minion wave. However the brief stun doesn't take effect until they're stationary in-front of him, so if your allies are close, be be prepared to use overdrive & power fist if they break his hold with a movement ability (such as flash, or ezreal's arcane shift). But be wary of when to use his overdrive, as the underdrive slows him after the boost, which can gimp an escape attempt.
Darius
Is one of the few great anti-tank tanks (juggernaut is just a subset), he can rubble a tank in drawn-out brawls. Obviously his weakness is that he has no mobility ability to speak of. His short ranged apprehend doesn't deal damage, but interrupts other animations and can reach over a handful of walls in the rift. Due to his crippling strike having no scaling with rank, always max it last but take it before level 6; it can be used as an auto-attack reset to get a few quick stacks of hemorrhage. Like teemo, this built-in dot can mess up his farming if he's under pressure, so crippling strike or decimate could be used for farming with good mana management. Despite his sluggish steamroller playstyle, he seems oddly effective at fighting yasuo in a duel; though his shield blocks some of the bleed & guillotine, the fake ninja's dash lands him in the axe path of decimate, and doesn't deny his crippling strike either.
Nautilus
His dredge line is similar to blitzcrank's rocket grab but with a few differences; it has a shorter but wider hitbox (for obvious reasons), can't go through terrain, and functions like a cross between blitzcrank's & amumu's grapples. Of the 4 hookshot style champions, he's the only one unable to grab across walls, but instead drags him to the wall he hits; meaning it's his only mobility ability, and not to be used lightly as it still has a noticeable cooldown. In most cases, it pulls him closer to the enemy champion than them to him (something about the center of hitboxes compared to relative mass), so if you nab someone, expect to go farther than halfway to them. And thanks to his sluggish attack speed, it's often best to wait a moment (.25~.5 seconds) to auto-attack after hooking someone in order to maximize the lockdown duration; however his grapple has the same weakness blitzcrank's has, so this forced delay isn't always a good idea. Titan's wrath gives his auto-attacks a dot & aoe, but won't reset his attacking animations either.
Tahm Kench
While not as imposing of a tank like the anchorman, he's just as effective at keeping an enemy pinned. If an assassin is trying to nuke your ally, eat the assassin; the assassin will outrun you if you try to save your teammate, this way you keep them from finishing their combo while they create more distance. This is particularly effective at denying buff reliant or time reliant ones (like master yi, nocturne, & tryndamere). However if they have extreme or spam-able mobility (katarina, ekko, leesin, ext) then this is probably stalling the inevitable without more teammates nearby. Note that at pointblank range, his tongue lash can be used as an auto-attack reset if he needs to devour the enemy immediately; but remember he can only eat one champion at a time, regardless if friend or foe so choose wisely depending on the situation. Also if they have some kind of continuous aoe effect, it will continue to apply around tahm too, so don't go walking into your team if you bite a spinning wukong.
Thresh
Unlike blitzcrank & nautilus, his grapple is on a significant delay, slightly longer than a second; so don't rely on it if you're not good at predicting. While his sweeping flay isn't sluggish, the area is deceptively small (barely reaching beside him, but mostly in-front & behind), however it's important to know that it can interrupt movement abilities and bump them into the direction you clicked if you time it right. However his ultimate box will not, and though it says it has a 99% slow, there's a minimum movement speed cap; and due to the cast delay, don't expect it to save an ally from an assassin. The shielding lantern from dark passage has similar leashing to orianna's ball, it can only be sent a fair distance, but doesn't return until moved noticeably farther away; remember that it has a lengthy cooldown too, so decide carefully to use it for the damage absorption or saving yank. Something often overlooked is that thresh has laughably low base armor, so don't go thinking you're durable until late game, collecting with the lantern is something handy if you don't want to get close.