FL becomes a stepmother / Guardian of a child

• Invincible Stepmother (stepmother)
• A Familiar Stranger (stepmother)
• Indulgence (guardian of a little girl)
• Just Between Us (stepmother)
• Warm Time With You (guardian of her nephew)
• Please Be My Family (guardian, the children  initially appear to be the FL's daughter and the ML's son but they're actually the leads' twin niece and nephew) 
• and Mysterious Love has the SFL becoming the stepmother to the SML's daughter

I’m currently watching  Bravo, my life which has this trope!