Here's some of my ideas for additional entities and updates to entities that already exists.
Spawns - [Priority]:
This would be another option in the human and zombie spawns.
You could choose priority (default), primary, secondary and so on.
When you create the entity it would be on default, which means that it will just pick random between other spawns on default. But if you add Primary to one spawn, then the first human / zombie would spawn there (Depending on what spawn entity of course). Also it could only be one primary, secondary and so on. Another alternative could be that you had for example two primary spawns, so that the first spawned human / zombie would spawn random in one of those, etc.
Instead of primary, secondary, etc it could be used numbers like 1, 2, etc.
Spawns - [Parent]:
In case you don't know what the parent option does.
The entity is following the entity you choose in the parent box.
This could be helpful to for example make spawns inside movable things, like trains and cars.
But it could also probably be used for just move the spawns around the map, if it's for example a zpo map, instead of having loads of them.
func_precipitation - [Hail]:
It's already possible to use snow, snowfall, rain and ash.
But, I don't know what snowfall is, is that hail? And if not, you think you could add it?
I don't think it would be to hard to implement, because it's basically the same as the other kinds of weather. I think it maybe got something with sprites to do.
Worldspawn - [Zombie lives amount]:
Can you add so that it is possible to decide amount of zombie lives from this entity?
That'd be much better than creating an extra text file for each map that needs maybe more zombie lives, like zpo maps. (I think the text files are .cfg types.
Weapons/ammo Entities - [Player-count activated]:
With this entity, you could choose a number from 1-31, if not more survivors.
And when so many survivors are playing, not total amount of players as it is often afk people. Then the weapons/ammo spawn would be activated. This could be in good use for making all maps balanced, no matter how many players, if the mapper takes time to make reasonable amounts of weapons & ammo for the different count of active players.
This entity is bugged. It only works when the "play everywhere" flag is checked on.
Please fix this.
If you decide to add this just change the name, that suggestion was the only one I could come up with. When this gets activated the humans inside the brush would die from no air.
Zombies don't need air (Because if not, they would be able to drown).
This would be good for example as trap, like an airproof room, with sealed doors.
Also, I believe this would be easy to implement. It's the same thing as drowning, except the sounds and the bubbles. Just remove the bubbles and replace the drowning sounds with choking. Oh, and the fact that it doesn't hurt the zombies
This could be an addon for the trigger_hurt entity. - Suggestion by Kommando.
In the end of opposing force you climb up and rope, and it moves. If you stop moving it stops too.
This would be really useful as I see many maps that use ropes instead of ladders.
The big downside is that it's not realistic that when you climb an rope it don't move at all + it sounds like an ladder.
This could be another option for the func_wall entity or for env_fog.
It's only invisible or partially invisible for the zombies.
This would be just like a normal button, except that it only got one surpose.
It would only target train entities, and a target path_track or path_corner for the train entity.
When activated, the train you chose would follow the path to that path entity you chose.
This could be helpful for making elevators with more than 2 levels.
I have no clue if any entities are similar to this, but if so just tell me, and I'll remove it.
This would be useful for objective maps.
This would be a no-collide brush entity. One option would be the master. While another would be several entitys. You could either make so only one, or several entitys named would have to be brought to the targetzone.
And you could choose things to trigger in the outputs afterwards.
Like maybe end game, or something before that. Like an explosion, which clears up an escaperoute. It could also be good for just making it harder to reach some areas of maps or to get good weapons somehow.
When activated, this would trigger a votemap for a new map.
This could be used for, maybe long big objective maps in case the players don't wanna play it again right afterwards. And if they want to extend map, they can just vote extend.
Or it could just be triggered by a button in a normal map, in a hard to reach area. Just in case some people have a big desire to change the map
When this entity would be activated, it would show a question at top, and several options below.
The content in this entity would be: Question: "Write message here".
Option 1: "Option1"
Option 2: "Option2", etc.
When an option would win the vote, it could trigger an event with the output/input.
Like, you add an output: OnOption1-win, "trigger something".
And you'd just add "x" amount of such outputs, one for each option.
And you could also make the last option be for example, "other", and let it trigger another game_vote entity, so that you wouldn't have to add so many options and outputs.