The key to a permanent-Silence team is that every time you hit a troop with a status effect, the timer for all status effects on it resets.
Euryali is the queen of this (every 4-match essentially reapplies all status effects), but Khorvash/ Mab / others are almost as good when combined with a transformer or troll to generate 4-matches. Hell, Leshy is killer provided your first troop is impervious.
I’ve been thinking about building a team to maximize this strategy but haven’t gotten around to it. It has the possibility of being completely overpowered though.