Shinypink.
It can be worth your while summoning other Shaman, even if you intially do very little with them, as you can use them to store the free energy that accrues during the day, like when you are not playing or sleeping .
Of course every Shaman has a use dependant on a players strategy.
However 2 shaman are worth having and using whatever your specialist strategy is.
#Baggi the Big, which you already have, will help you to build things faster, and apart from the competitions where they offer charms as prizes, Baggi is the only one where you essentially get free charms, that is,without spending real money on packs..
However, you will still need to buy them from the clan store, which means you have to be in a clan to collect clan points from clan tasks.
# Inga the wise, is the other, as she helps with reducing research times, and has other benefits too.
Once summoned they just sit in the Hall of Mysteries where you can switch between them as necessary.