Absent by Design Mod 1.14.4/1.12.2 adds some (but not all) missing fences, walls, stairs, and slabs. It also adds models and code for the blocks; adds zero textures. The mod pulls textures from the relevant source block. It can be overridden with resource packs as normal.
Note: Compatible with all resource packs.

Features:
Fences include:
- Quartz
- Red Netherbrick
- Wooden logs
Walls include:
- Stone
- Brick
- Sandstone
- Endstone
- Purpur
Slabs & Stairs include:
- Stone types
- Endstone brick
- Netherrack and Red nether brick
- Concrete
- Prismarine
- Coarse dirt
How to install:
- Make sure you have already installed Minecraft Forge.
- Locate the minecraft application folder.
- On windows open Run from the start menu, type %appdata% and click Run.
- On mac open finder, hold down ALT and click Go then Library in the top menu bar. Open the folder Application Support and look for Minecraft.
- Place the mod you have just downloaded (.jar file) into the Mods folder.
- When you launch Minecraft and click the mods button you should now see the mod is installed.
Absent by Design Mod 1.14.4/1.12.2 Download Links:
For Minecraft 1.12.2
For Minecraft 1.14.4