Status Cake

Colors :  Purple (#3e1336) and Gray
Fonts: Arial, Helvetica, sans-serif 


Elastic Cloud

Colors : #3F3F3F, white 
Fonts: -apple-system,BlinkMacSystemFont,Segoe UI,Helvetica,Arial,sans-serif


PingoMeter

Colors : #4c5964, #18252d, white
Fonts : proxima-nova,Helvetica,Arial,sans-serif

Profile icon clicked ⤵

Help button clicked ⤵


Monitis

Colors : #141414 , #c5c5c5
Fonts: arial, tahoma, helvetica, sans serif


DataDog

Colors : #332d39, white 
Fonts: OpenSans,Lucida Grande,Lucida Sans Unicode,sans-serif


Netflow Analyser


Flow

Colors : #49a9f9, white
Fonts: Tofino,Helvetica,Arial,sans-serif


Xero

Colors : 
 - Banner : linear-gradient(#048abb,#048abb) , 
 - Background : #f1f4f5 , white
 - Text : Black
Fonts: arial,helvetica,sans-serif


Sentry

Colors: #2f2936, white
Fonts: Rubik,Avenir Next,Helvetica Neue,sans-serif


Helpscout

Colors: 
 - Banners : #1f5e89, white, black. 
 - Menus : black text on a white background. 
 - #194c6e for all other text.
Fonts: "Aktiv Grotesk","Helvetica Neue",Helvetica,Arial,sans-serif


And you’ve already seen

Asana

Colors:
 - Sidebar background : #151b26
 - Text : Black on white, White on darker backgrounds
 Fonts: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Helvetica,Arial,sans-serif


I really liked Status Cake and PingoMeter. The former slightly resembles Sentry as well.