Dungeons & Dragons 5e
(Player’s Handbook p.93) The Beast Master ranger battles monsters with the aid of a wild beast companion which follows them and fights with them and with which they can share spells which they cast upon themself.
(Fizban’s Treasury of Dragons p.15) Drakewardens are rangers with a special connection to dragons. Drakewardens gain the Thaumaturgy cantrip, learn draconic, gain a drake companion which starts small but grows to be large in size over time, and which eventually can fly and carry the ranger. Meanwhile, the ranger and their drake gain resistance to the damage type chosen as the drake’s essence, which it does as attack damage. Eventually, you can produce a dragon’s breath weapon yourself, and provide damage resistance to yourself and your drake to a specific type of damage done to either of you.
(Tasha’s Cauldron of Everything p.58) Fey Wanderer rangers have become fey-touched in some way. This touch of the fey allows them to be more charming (both naturally & magically), as well as protecting them from being charmed themselves. In addition they can summon fey beings to help them and they find it much easier to cast misty step, so easy in fact that they can even invite friends to join them in their misty steps- a misty pas de deux, if you will.
(Xanathar’s Guide to Everything p.41) Gloom Stalker rangers love the dark places of the world, whether that be the Underdark, deep in dense forests, or the hidden parts of cities. They get a bonus to their initiative and move faster in the first round of combat and get an extra attack on that round which does increased damage. Their darkvision increases, and while they are in the dark they are invisible even to creatures with darkvision, which is pretty amazing. They are proficient in WIS saving throws, when they miss an attack they can make another attack as a part of that attack, and they can impose disadvantage on attacker’s rolls. These super stealthy rangers can sneak up on most things as long as it’s dark out.
(Xanathar’s Guide to Everything p.42) Horizon Walker rangers protect the world from forces from other planes. They can sense planar portals within 1 mile, they add force damage to their hits, and they can cast etherealness without using a spell slot. They can teleport when they attack and they get an extra attack when doing so if they have attacked twice that turn, and they can also use their reaction to gain resistance to a hit’s damage.
(Player’s Handbook p.93) The Hunter focuses upon hunting down the greater threats to civilisation found in the wilderness in Dungeons & Dragons: dragons, giants, ogres, or hordes of orcs, hobgoblins, goblins, or the like. These rangers can choose from a variety of special skills which make them particularly effective against those types of foes, both defensive and offensive, like providing the hunter with extra attacks and doing extra damage or giving the hunter evasion or uncanny dodge. There are a lot of goodies to choose from in this subclass, and the difficulty will be in choosing which of the several good options you will pick each time a choice must be made.
(Xanathar’s Guide to Everything p.43) Monster Slayer rangers have dedicated themselves to slaying magical creatures which are threats. They can determine if a creature has any damage immunities, resistances, or vulnerabilities just by spending an action looking at it. These rangers can also cause increased damage on a creature that they are focused on as prey, get bonuses on saving throws and rolls to escape grapples by their prey, and can stop someone from casting a spell or teleporting. They can also attack any creatures forcing the ranger to make a saving throw, and if the ranger’s attack hits then the saving throw is also an automatic success.
(Tasha’s Cauldron of Everything p.59) Swarmkeeper rangers LOVE swarms of teeny tiny creatures, versus one or only a few larger creatures. For them it is always quantity over quality. A swarm of creatures of their choice follows them around, like Pig-Pen from Peanuts, but unlike Pig-Pen’s cloud of omnipresent dirt, the ranger’s swarm aids them in battle and generally are a comfort to them. The rangers can even become part of the swarm themselves, moving in safety with the swarm to another area nearby. Plus, the tiny critters in the swarm can even work together to make the rangers fly. Very slowly. It would be tricky, but imagine that their swarm was composed of European swallows- they could all work together, by connecting strands of creeper to the ranger, to build up the air speed velocity required for flight. Anyhow, you get the idea.