where can I get a preset for 1.13.2 that has classic generation of terrain like it was in beta Minecraft, and is there a way someone could make this if there isn’t ? Please help
I really don't think presets will do that!
You'd need a mod.
If you know of any mods please list them as well
There are no mods for 1.13 yet (aside from some non-Forge/MCP dependent mods like Optifine); you'll have to play in 1.12 if you want customizable terrain, either in-game or with mods (here are some presets that you can use in Customized to get similar terrain to Beta).
TheMasterCaver's First World - possibly the most caved-out world in Minecraft history - includes world download.
TheMasterCaver's World - my own version of Minecraft largely based on my views of how the game should have evolved since 1.6.4.
Why do I still play in 1.6.4?
How come I can’t customize terrain in 1.13.2?
Appearently Mojang are working on the customization system to make it easier to use.
So hopefully customization will be back in 1.14