Before whatever version of MC that was where they redid the entire ID / model system I was making a mod for Minecraft that as is typical for new modders was mostly a mix of "Here's my 'improvements' for the game" kind of thing.
As well messing around with my growing ability by just making whatever seems cool. So here are some highlights I was proud of.

Ultimately the philosophy of the mod was "Stuff that felt like they would fit in Vanilla", with an emphasis on "No GUI".
You can click any images to see fullsize ones. As well this doesn't show everything, just elements I felt worth documenting here.

As I worked on the mod more unique and advanced features were added as I grew to know what Forge was properly capable of. Here are a few enchantments that I feel were pretty unique and cool:

Permanence I, II (for any Item): At Level 1 that item will not despawn. At Level 2 it cannot be destroyed by conventional means, as well it floats on water.
Sturdy (for Pants): If you experience mortal damage that would kill you instead you remain at half a heart briefly. Based on the Pokemon ability of the same name.
And of course, something silly: Squeaky (for Weapons): Causes your weapon to emit squeaky toy noises when you hit stuff.

Cool Decorative Blocks

Tiles before we got Vanilla tiles. ..imo they look better too..

Neato Items! :O

Bugs that provide a variety of utility functions such as Harvesting, Chopping, Breaking Leaves and Smelting. You got them by breaking tall grass.

The Ball of Existence, click a handful of items and when you right click the ball the items vanish and reappear in the blink of an eye. Very fun item, and worked in Dispensers to so they could be automated.

Functioning Blocks

SCAFFOLDING! Genuinely, in my opinion, the best version of Scaffolding in mods or vanilla. To the point I nearly released it as a standalone mod. Biggest feature it offers is hotswapping scaffolding with blocks of your choice.

What's a mod without a custom crafting system? The Lightning Forge functions as a Lightning Rod and can craft and transform certain items when struck by lightning. The code was simultaneously very sophisticated, and extremely jank. As it accounted for other forges in a chunk with the higher taker prcedence. And the recipes were disgustingly hardcoded.

The 3 Mobs I Made

The Smoke Monster, a spooky mob that utters bizarre whispers. Capable of scaling cliffs, breaking down doors, and fitting through tiny gaps it seeks to suffocate anyone who draws near. Spawning rarely in forests and caves, it fears the sun and water. I loved this spooky lil' guy.
A Tumbleweed! Where's the picture you say? I never got a good demo photo back in the day.. This guy was my king of my vanilla philosphy. It was practically a roaming hopper, picking up any items that it came across. The intent for the player to utilize them as item holders and discover unique ways to do stuff with them.

The one everyone loved: Trumpets. Playing adorable trumpet riffs, they were essentially Bees. Flying around flowers and causing them to pollinate and grow more flowers. As well attacking 1 made the group attack you. I loved these guys.