Tigger

noun2

1. •
   An overly enthusiastic or energetic person, often characterized by bouncing.

   • Whereas Olivier, particularly when first nights approached in which he was appearing, invited protectiveness from those around him, Hall was sometimes like a Tigger whom others wanted to unbounce. — 1978
2. •
   (UK, informal) A member of The Independent Group for Change, a pro-European British political party that existed in 2019.

   • Nor is there any sign that Corbyn is at present willing to make any overtures to the eight Tiggers and those who may be contemplating joining them. — 2019