I dont have any topo maps of lakes that I can post or I would. But I can tell you basics of what info you can get of a topo map that will help you in fishing. I do however have access to a non water topo map and will show you what I mean on that it will carry over if you buy one for the water.
The lines on a topo map indicate elevation, which can show you depth on the water that is important to know sometimes. But I'm sure you figured that part out. (on this map each line = 20ft and we see about 100 ft)
Other stuff the closer the lines are together indicate grade or steepness. When lines move really close together this is usually a drop off whiche depending on the species you are targeting may be a good thing.(on this map we see in about the same space as the previous map a 500 ft drop in elevation)
Like wise if the lines move farther apart this shows plains, shelves, or long flat spots. Depending on the lake these can be long sandy bottoms which may be good to know as well.(image we see about the same area of the map and it only gains about 35 feet)
Closed circles, these indicate peaks or depressions which on a lake map would show the lowest bottom or deep holes.(these are usually marked with an elevation so you will know depth)
Valleys, channels, V's or U's these can indicate valleys on land maps or on man made reservoirs, but can also mark channels which are usually cut by current. So if you see one of these cutting threw a flat spot its probably an inlet which in Colorado usually means warmer water meets colder water and can be great to fish, again depending on species.
Well thats all I can think of now but I hope you see how this can be an extra tool to use when scouting lakes, it however may not be the best tool to use by itself. A good depth finder can point out where you are on the map or a gps. Structure like fallen logs arent shown which help ambush predators or provide protection for baitfish. There are lots of stuff to make a good map better, when looking for lake maps try to get the map to have a scale of each line = 5ft or less 20ft lines may not be good for 40ft deep lakes.