SkyBlock is a great map.
Survival maps are constantly being created by people in the community, so there's probably thousands of maps by now, or even more! If you want to look at some then some good websites are 'Planet Minecraft' or simply the Minecraft Forum.
Just Yahoo/Google "Minecraft maps", go to the minecraft forums or go to Youtube and look at some of the videos. They some times put a link to the map in the description of the video for you to download.
none citywars has custom plugins
I cannot speak about all the maps, because I have not downloaded them all but you can't tell if it does if your only criteria is "a minecraft map." however, actual, normal minecraft maps do not contain any viruses. If you want, you can scan it for viruses with some software
Some might, but an adventure map is a MAP, not a mod. Just search for "adventure map" on Google or the Minecraft Forum.
Good seeds vary between different Minecraft versions.
On most websites, Minecraft maps are free. Some websites might charge you for downloads, so be sure to review all information given by the site, and if you're still unsure you can contact an administrator.
Go to Plazma burst and go to Custom Maps
You can search for Minecraft servers on websites such as Minecraft Server List and Planet Minecraft. Some popular servers include us/eu.mineplex.com, play.cubecraftgames.net and play.hivemc.com where there are a bunch of plugins, custom gamemodes and minigames for you to check out.
They may be outdated, not only the map version but maybe some of the redstone used.
well most minecraft maps have texture packs not mods so the map I would recommend for a map without mobs I would download deep space chase or frozen dragon
Planet Minecraft and Minecraft Wiki are two sites i can think of.