Better OgreLair for Minecraft 1.12.2
The Better OgreLair mod was supposed to be an add-on to the famous Mo’ Creatures mod, but something went wrong. Then the designer decided to release a separate mod that would not be associated with other add-ons, so it will work fine standalone. The game will now feature a new dimension, which is very interesting and unusual. You will be able to both travel there and diversify your in-game life, as the ordinary game world may have bored you , and you would like to explore something new.
If you are tired of boring dimensions, not to mention ordinary worlds, and looking for a mod that will diversify your travels, then the Old Time World add-on will perfectly suit you. This mod will add a new dimension to the game and take you back in time. You will find yourself in a world with dinosaurs. It will be filled with numerous dangers, and one wrong decision there may lead to your death. 
Crocodilite is a small add-on that cannot work without other mods. The fact is that this mod was created specifically for the Underdog modpack, but you can try to use it in combination with other mods. It adds the possibility of creating blocks as well as other elements that could not be created using ContentTweker. 
If you are tired of the usual functions and would like to diversify the vanilla Minecraft with new add-ons, the Just Needed mod will perfectly suit you. It does not change the game beyond recognition; on the contrary, it simply complements it with some useful ideas. 
Aqua Acrobatics is a useful add-on that diversifies in-game swimming. The game will now feature several new bodily movements conducted during swimming. Besides, it will be possible to change the swimming speed — this will allow you to move through the water in different ways. Also, this mod reduces the sneak height to 1.5, thereby allowing you to go through smaller gaps. 
Flour Power is a useful mod that will allow you to make flour from wheat. In turn, you will be able to cook the same food that is associated with wheat from it. The new updates of this mod make it possible to bake cakes and cookies. And the most important feature is related to cooking bread even without the crafting table. 
The Palamods add-on brings new items related to the fallen kingdoms. The game will now feature five ore types, which will diversify the game world. It will be possible to find a lot more ores in the mines, which will significantly improve your mood. 
Mappet is a small add-on that diversifies the in-game tools. The game will now feature new toolkits, which will have some advantages compared to the vanilla items. The mod will allow you to make your adventures much more interesting thanks to the new items. 
The Infinity Pickaxe add-on is quite unusual but at the same time very useful. The game will now feature the infinity pickaxe that will allow you to break everything you want very quickly. So, you will have a unique opportunity to instantly destroy any block. 
Tinkers' Reforged is an interesting mod that adds a lot of building blocks brought from other add-ons. The game will now feature quite interesting blocks, and you will be able to use them not only for building structures but also for other purposes.