"Common things are common" is a phrase familiar to medical students learning about differential diagnosis. There have been a lot of common things to see recently when I have been out and about this summer.
The common darter (Sympetrum striolatum) is certainly the commonest dragonfly at the moment.
Common hawkers (Aeshna juncea) are less common than common darters and seem to be less common than southern hawkers.
Common blue damselflies (Enallagma cyathigerum) are still the most numerous at this time of year.
Common blue butterflies (Polyommatus icarus) are the only blue butterflies I have seen this year.
The common carder bee (Bombus pascuorum) is by far the commonest bumblebee in the garden just now.
The common green grasshopper (Omocestus viridulus) is common but not always green.
Common lizards (Zootoca vivipara) are not common but I was lucky enough to see several last month.
Common means "prevalent, or occurring, found or done often". It can also mean "vulgar or lacking refinement", which certainly couldn't be said of my common pheasant (Phasianus colchicus).