One group of die-hard campaigners who have previously defied the military's ban on political protests said they planned to march to a court in Bangkok to file treason charges against junta chief Prayut Chan-O-Cha.
Student activists who have previously specialised in creative "flash mob" acts of dissent have also said they will hold protests in downtown Bangkok on this evening.
Their efforts have included public readings of George Orwell's anti-authoritarian novel "1984" and flashing the three-fingered salute from the Hunger Games films which are set in a dystopian dictatorship.
Two weeks before the military coup and the imposition of martial law, Yingluck had been forced out of office by a court ruling.
Her supporters say the coup was the latest assault by the royalist Bangkok-centric elite on the kingdom's burgeoning democratic forces - in particular from the culturally distinct northeast, which voted in droves for Shinawatra parties.
Protests have been smothered, dissenters arrested and anti-coup radio and television stations shut in the past year.
The junta says its power grab restored order after months of sometimes violent protests against Yingluck.
But small pockets of dissent remain.
