If you haven't tried them, I recommend giving them a try. They all have something to offer.

I don't use Gnome, for example. People knock on it a bit BUT a large group of people swear by it for workflow.

KDE Plasma is the dream for anyone who likes to tweak settings. I used it on my laptop for a long time and it is very convenient. It also manages power and monitor settings very well. In terms of memory usage it is now similar to XFCE.

XFCE is perfect for people who don't like change. It is a slow moving DE; tried and true.

Right now I am using LXQt. Not sure why I decided to do that. It looks ok. It is fast and light. That's it's claim to fame. It can be used with different WMs which is nice.

Are there any particular DE’s you like on a laptop, because of things like power consumption and efficiency that would not come normally into consideration for a desktop?

I can't say I've ever looked into it. But, I found that KDE handled things very well. I used my laptop for full workdays, getting 11 hours out of it.

i3
the less I need a mouse on a laptop, the better

edit: ok, you specifically asked for a full fledged DE and not just a WM. well, I picked what I needed and with Manjaro i3 as base, I had a nice place to start

Tiling window managers like i3 are imho nice for laptops, since they do not waste any space and can be easily controlled via keyboard. Takes a while to get used to them, however.

XFCE minimal but good looking. You could also go for MATE or Cinnamon..

GNOME

i3 and never looked back!

xfce since it came default with eos and its pretty lightweight

Of the ones I tried, my top 3 would be cinnamon, budgie, and kde. KDE is probably the best bet for modern features ATM, cinnamon for simplicity.

On laptops Gnome has a big advantage in the multitouch gestures for the touchpad, and as everyone says it's pretty polished. But lately I've been using KDE since it offers a lot more functionality and customization out of the box. Most of it's apps are like a swiss army knife and I love that. KDE is also catching up in the multitouch gesture department.

Plasma. I have it configured to match my workflow.

I'm the type of person who gets tired of a DE after using it for too long, so I'm using Budgie right now and I really like it. However XFCE is pretty nice, too, it's what I used to use.

I recently switched to xfce.
I used KDE exclusively since 2004. That's a very long time but KDE Plasma in combination with nvidia got worse, what felt like, every single day over the last years, so it finally came to the point where I had no choice to look for something that works better.
Super happy with xfce after I set it up almost exactly like my KDE setup. Sure there are some thing that are not as "well rounded" than some of the excellent Plasma features but over all it works great!

@aMalayali KDE - desktop or laptop.

GNOME, despite the critiques it receives it's the most polished one and the one that gives me less problems

Gnome hands down has the best laptop experience. If you follow the intended workflow of using tiled windows and many workspaces. You can get to a very large number of windows, without getting lost, even with just the laptop screen.

Additionally the paradigm does translate well to a desktop for the times you are docked.

I like Enlightenment. It uses 400 MB of RAM on my old laptop/

Cinnamon for me, It looks like old Windows

I use kde on my laptop

I'm a KDE guy and use it myself on my notebook, but GNOME with its multitouch gestures and polished (if a little inflexible) workflow is also an excellent fit.

sway, the i3 clone for Wayland. I'm really happy with it, even on my Intel iGPU + Nvidia GPU laptop.