All things associated with summer and the beach.

Mugs, teacups, glasses.

All things associated with beverages & drinking vessels.

Woolly jumpers, Sunday roast dinners, farming?

Sheep can or must be involved in all, it sounds like.

Apples, pears, persimmons.

They’re all fruit.

Granny smith, sun crisp, pink lady.

These are all types of apples!

Navy, sky, cornflower.

All three words are a type of the colour blue

Battle, merchant, liner

Those are all types of ships!

Plate, bowl, saucer.

Three items of crockery. All that is missing is a teacup.

Bungalow, flat, cottage

Typically of one story.

Rabadash, Eustace, and the Lady of the Green Kirtle.

All three became non-human creatures: Rabadash became a donkey, Eustace became a dragon whilst the Lady of the Green Kirtle became a rather too large boa constrictor type snake. 

Chisel, saw, drill

All are handtools.

Lions, zebras, springboks.

All animals that originate in the Southern part of Africa. 

Kangaroos, Koalas & Dingoes.  

All animals found in Australia, though only the first two are genuinely native (the dingo was introduced at least 3,500 years ago from SE Asia).

Harfoots, Stoors, Fallohides. 

All hobbits, featuring in JRR Tolkien's epic stories. 

Nutmeg, Pepper and Cloves