First, Iko is using only client-side mods, that mean that you will be able to play on any (none-modded) server !

Majority of mods are configurable by just going into:
Echap>mods>click on the mod that you want to configure>then click on the little setting icon on the right top.

List of all the mods

Disclamer: These mods are not my mods, all credits go to their creators

If you want to know more about a certain mod, just click on it to go to his forge page

Sodium, Lithium and Phosphor| are some incredibles mods that optimizes games better than Optifine

Advancement Plaques| just makes advancements look better

Controlling| improve the keybind menu (by adding a search bar for example)

Eating Animation| well, that add animation when your eating (is no compatible with some texture pack)

Litematica: one of the best building mod ever created

Screenshot to Clipboard| Well... when you press F2 your screenshot to yout clipboard

Skin Layers 3D| just make the skin's overlay more in 3D

AppleSkin| Allow you to see your saturation and how much food & saturation each food gives you

Better Ping Display |

Dark Loading Screen |
Low Fire | well everythings is in the name
Mod Menu |
SlotLock |

Blur| put a Blur effect when you are in a menu

Detail Armor Bar| show the armor material on the armor bar

Dynamic Sound Filters| improve the sound of Minecraft by adding resonance when in caves for example

Fabric Capes| allow you to see your optifine cape even if you are not using optifine

Full Brightness Toggle| by pressing G you can toggle full brightness

Inventory HUD+| a really good mod that can display potion effect, armor status and more...

Iris Shaders| An amazing mod for shaders

LambDynamicLights| do the same things as the Dynamic Lights options in options

Ok Zoomer| allow you to zoom

Presence Footsteps| make every bloc have a special sound when you step on them.

WorldEdit| well i thinks i don't have to explain this mod

What add the Iko-V2 ?

Command Macros| Allow you to run custom command by just pressing a key

Mouse Tweaks| Allow you to do many things with only your mouse

Sorry if the spelling is not perfect I am french 😅