The Blue-tailed Damselfly/Common Bluetail (Ischnura elegans) boasts a glittering array of different colour form females. The normally documented forms number 5, 2 of which are immature colour variations and 3 of which are mature. The immature males introduce a 6th colour form with a turquoise thorax. Those are the colour forms that most [all?] of the books document.
Here is my chart attempting to demystify this colourful potential confusion.
To trap the unwary, one of the mature female forms is androchrome, resembling the mature male. Furthermore, there are instances of females that fleetingly resemble immature males (it’s a transitional phase], so it’s useful to know how to determine gender without recourse to colour.