Sleuths of a Certain Age

When her daughter is accused of murder, widowed Kausar Khan returns to Toronto to clear her name. She left her tight-knit Southeast Asian community almost twenty years ago in a cloud of grief and depression after her youngest son's death. As she investigates, Kausar begins to make amends with her daughter and her old friends and get to know her granddaughters. Like Miss Marple, Kausar is aware that people treat women over fifty as invisible and naive — but they underestimate her keen powers of observation at their own peril. She plays into the meddlesome aunty trope to suss out the real killer.  First in a series.
 

When she finds a dead man in her San Francisco tea shop, widowed Vera Wong calls the police — but she's sure she could do a better job than they could finding the murderer. After  all, she's a meddling Chinese mother. She steals the victim's flash drive and helpfully draws an outline around the body like she's seen on TV. The police are not pleased. But Vera is bored and lonely, and she launches her own investigation. She collects a group of customers, including the dead man's widow, who all have secrets of their own. Vera is a hilarious and endearing heroine. First in a series, and the second one is already out! 

Four quirky septuagenarian residents of a quiet English retirement village meet every Thursday to chat about unsolved cases. There's the mysterious Elizabeth, retired union leader Ron, former psychiatrist Ibrahim, and former nurse and new resident Joyce. After a local developer promises to block the sale and redevelopment of the retirement village, he turns up dead, and the Thursday Murder Club decide to tackle their first real case. This series is clever and witty, but also deals thoughtfully with the indignities and worries of aging. First in an enormously popular five-book series, with a Netflix adaptation!

This time, our narrator Billie and her friends are four women in their sixties who've worked together for forty years at the Museum. Except this museum isn't the Smithsonian, it's an elite network of assassins. Billie, Mary Alice, Natalie, and Helen are sent on an all-expenses-paid cruise to celebrate their retirement, but when the yacht sinks, they realize their bosses never intended for them to come home. Now they're on the run, and they've got to rely on each other to outwit the agents sent to kill them. This one is more of an action-packed romp than Miss Marple, but if you like competent, funny women, it might be the read for you. Also first in a series!

Seventy-seven-year-old Judith Potts lives in a mansion near a sleepy British town and enjoys wild swimming, Scotch, and devising crosswords. While swimming in the Thames one night, she hears a cry for help and then a gunshot. The police claim it's probably just a car backfiring, but the next day her neighbor is found dead. Judith decides to investigate with the help of a local dog-walker and the vicar's wife. This is a clever cozy mystery, first in a four-book series, and there's a PBS miniseries adaptation!