I think you can easily do this in the Simple Automations App, but you'd need to create an automation for each Light. Probably not exactly what you're looking for. You probably want a custom App, correct?
Update: Actually, I don't see the option to add a delay in Simple Automations when using a switch as a trigger... 
I tried to set this up with Simple Automation Rules right now, but couldn't find a way to delay the "off" action based on the "on." I don't use SAR (formerly Simple Lighting, which it may still be called if you're running old hub firmware) much, so I might be missing something.
I did write an app that should work for this: [RELEASE] Timed Switch Helper. My intent was actually to use two different switches (in my case, something like a "timed fan" virtual switch that would turn on the real fan switch for a certain amount of time, then turn it off), but I don't see why it wouldn't work for the same purpose that you're aiming for if you just choose the same switch for both the "virtual"/timed and "real" switches. Ignore the rule I wrote in that post--it's from Rule 3.0 and would be quite different in 4.0, which is what you'd have if you just installed RM.
I also looked at something similar earlier today with my bathroom fan, setting up a rule to turn it off after a period of time. It doesn't solve your app based approach, but thought I'd mention it as an alternative in case you find it useful. I also plan to try out @bertabcd1234 's app as well. I have a couple of virtual switches on my dashboard I use as a way to turn off lights more quickly than their timeout setting if I want, which would fit nicely into that model.
Simon
This may not meet all your goals but many switchs/dimmers have a turn off time built into the driver.
I wanna avoid creating millions rules for every single switch, its already difficult searching for rule. That will work good for 5 devices not for 70
I looking for table with all devices on one side and time entry on other side.
Not parent child monster with spicial child with every device. I wanna see all devices at once.
Custom app time. I have same issue that why I lumped the three into one rule cause I didn't want loads of apps/rules
How about if you wanna different times for different devices?
Like
hallway 2min
Living room 180mi
Front porch 15min
Deck 60min
....
Mine were for devices that don't get used much
This is such a simple thing which could be done with a simple parent/child app
Trigger = switch on...
Timer starts... -> timer expires
if still on ... switch off
It wouldnāt take too long to create such a simple thing.
Andy
Not parent child monster with spicial child with every device. I wanna see all devices at once.
If i have to click on every device to edit it. I can as well do it in RM
Simple, if you want them all to have the same timeout.
A lot more complex if you want different times for different devices in the same app
I get your wanting to avoid RM (sort of), but do you really have millions of lights in your home that each need a different time or do you just have a handful? Seems that by now you could have written quite a lot of these very simple rules. No offense intended. Just seems like itās more time spent on this thread than the actual task would consume. 
agreed,
the whole purpose is to have a single place where I can limit time per device.
because right now with 3 pages of the apps is just difficult to find an app.
if I add another page of simple rules it will just make it more complex.
this is sole "convenience", in a perfect world all my rule doesn't have loose ends.
with 3 hubs it is somewhat less easy.
I think I have all my automation in good shape but occasionally some light or device doesn't turn off,
this will be a simple way how to prevent complex environment fail.
If I have to add another page of apps it will be just counterproductive. Even in this stage, I don't think my system can be maintained by anybody who is a newbie. I want that members of my family are able to change settings occasionally and not to "study" many pages of apps before they can change a simple thing.
not really to avoid RM, I use probably 15 RM
it is just not good for this particular use.
I find still easier to use the rule machine than write my own app.
maybe over time, hubitat guys will implement some global power allowance app in firmware,
since it simplifies use and its probably most basic rule in use by most people in some form.
Have you considered maybe virtual dimmers as simple controls to set the timeout? Should be doable in RM.
Yes,
can you imagine creating 100 virtual devices,
click on each each,
setting timing,
tieing them to real devices
setting rules?
It just increase possibility for error
I think if i dont see all devices at once,
in one plain table just to click to use or not, and add time,
it wont be worth it doing it.
My loose ends rules are pretty rare, its easier deal with occasionaly turn forgotten fan or light off manually.
You have 100 devices that you want to control this way?
Each with a separate timeout?
It is doable in an app but I donāt see anyone else using this.
This would take a considerable amount of time to code so itās difficult to justify this amount of effort for one user.
Andy
Yes, hence my original question if it exists. Not asking to make it.
Looks like it exist now:
Download the Hubitat app
