In the Netherlands we have this: https://en.wikipedia.org/wiki/Numbered-node_cycle_network
That works super well cause you can just follow the numbers. You can have those on a piece of paper if you need, or memorize the intersections where you need do something else besides following the next numbered node (so for example you go 25-26-27-28-51). You can just remember to keep following the next one until you need to go to 51.
Normal street signs look like this: Verkeersborden in Nederland https://nl.wikipedia.org/wiki/File%3ANederlands_verkeersbord_K7.svg
The color scheme indicates it's for cyclists. For motorized vehicles they're blue with white letters. In cities there are also signs for pedestrians which are black with white letters.
And there are also these for cyclists, in rural areas: https://en.wikipedia.org/wiki/Padstool_%28signage%29