is there a way to access planks and beams in creative mode in singleplayer? and is there a way to access ramps and etc in creative mode

well you can still use the crafting benches in creative mode and in addition to that you can access all of them from your inventory's crafting tab (by clicking on where it says Recipes:Default with red letters you can scroll through all the crafting stations)

there is also the console commands for produceing pnb.

item woodplank amount texture
item woodbeam amount texture
item woodlog amount texture
item woodplanktriangle amount texture

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Quote from Minotorious

well you can still use the crafting benches in creative mode and in addition to that you can access all of them from your inventory's crafting tab (by clicking on where it says Recipes:Default with red letters you can scroll through all the crafting stations)