The first game which has an inventory is Skyrim, it uses a fairly simple, if sometimes cluttered, inventory using a weight system, it has separate menus for things like items or spells, which then provides sub-menus to make it easier to navigate through things such as weapons, armour, scrolls, books, ingredients and potions.
Skyrim's inventory uses a weight system, more powerful items can sometimes weigh more, making you think about what you want to take with you, in some situations, you may be forced to drop items when exploring as going over the carry-able weight causes the player to become over-encumbered, making it very difficult to move around by disabling running, sprinting and also disabling fast travel.
When browsing the inventory you can see what the item currently selected looks like, you can freely move the object around on a point, you can also zoom in to take a closer look at the item, this is especially useful due to some items having important information on them, using the zoom on a book or note will allow you to read it.
There is also a quick menu, which allows you to access favourited items quickly mid-game, it is extremely helpful during combat as it allows you to change weapons, armour and spells that are equipped and also allows you to use potions or poisons.
The second game I chose was Borderlands 2, the inventory is a limited space inventory, which allows you to carry a set amount of items, regardless of shape, size or type, though the limit is upgradable shortly after the beginning of the game, the inventory features up to four quick slots for weapons, a slot for an active shield, active grenade mod, active class mod and active relic, there is also the backpack which allows you to carry up to 27 slots for inactive items .
The UI is fairly simple and not so easily cluttered, due to the item limit, it displays important information to do with the items such as the damage rating, accuracy, rate of fire, reload time and clip size, it also displays an effects change and damage if applicable, along with extra bits of information such as a weapons zoom, ammo consumption and if the weapon is a disposable one.
The items name will be different in colour depending on the rarity of the item.
There is also a little extra 'badass rank' feature which allows you to modify stats of weapons slightly, this feature can be disabled.
My third and final game of choice was Torchlight 2, this game features a tile inventory, it allows you to easily sort the items in the backpack and also supports drag and drop for things like equipping items and storing them in a chest or trading between pets or other characters.
The UI for Torchlight 2's inventory is more helpful than in other games, due to when hovering the cursor over an item or weapon, it shows not only the information of the highlighted item, but for the equipped item or items that are used in a similar fashion as well, allowing you to compare items similar to the currently equipped ones much easier, it also tells you if the weapons use fast or slow attacks, if they have any empty sockets for augmentations, what augmentation effects a weapon has, what damage type the weapon will deal and how much damage it will deal.
You also have a pet in the game which has its own separate inventory, you can equip it with things like collars and tags but the pet can also be used to carry items back to your storage in town or as extra storage during a dungeon.
The things such as collars and tags can upgrade the dogs combat efficiency by improving damage, health and regeneration.
