I liked Agua, Agualemon and particularly Pills themes, the colour of buttons were vivid and plain.
I also liked Kindakar, Kermic and Tux for the title manipulation.
In short my effort is a mimic of some really good Themes by the guys above. Thank you

My buttons were made by just drawing a circle filled with colour and then >Filters > Bevels >Pressed Steel used in Inkscape.
I have added a yellow area, this is so I can easily see which window is open.

To Install:
If you want to install system wide, extract to /usr/share/themes/.
If you just want to try it then extract to ~/.local/share/themes /. if the themes folder is not there then install it. As you are installing into your home directory there should be no tears.
You have to logout and back in again to see your changes, if you extract to /usr/share/themes/

If you are a newbie, this is what I do.
Open a Terminal
type:

cd ~/Downloads
tar -xzvf Peggy.tar.gz
cp -r Peggy ~/.local/share/themes/

line 1 moves to the Downloads directory from wherever you are.
line 2 extracts the file Peggy into Downloads directory.
line 3 copies the Peggy directory to ~/.local/share/themes/. Its in your local themes directory

Take a look at Peggy. Next save so you can use again:

cd ~
mkdir store
cd store
cp -r ~/Downloads/Peggy.tar.gz ./

line 1 moves to home directory.
line 2 makes a store directory, call it any name you want. this will store all your bits you want to keep from Downloads.
line 3 move to new store directory.
line 4 copies Peggy.tar.gz from Downloads to your store directory.

next clear your rubbish :

cd ~/Downloads
rm -r Peggy.tar.gz Peggy

line 1 move to Downloads
line 2 delete Peggy.tar.gz. I keep Downloads clear as possible so I dont get confused or clash with another downloaded package.

Files preceded with a dot are hidden files ie .local is hidden.
To see the .local file press >View >Show Hidden Files on the File Manager.
To see the .local file in Terminal type
ls -a

to see both hidden and normal file type

ls -al

Lastly goto settings and change to Peggy. its done.

I know there is a million ways to do this, you may do it with less commands.
I remember being new myself and it takes ages to find the answer you want.
Hope you like it.