I would save it, in case you need to repair/patch in the future (for example, at the base of the toilet, or if you change the flooring in the adjoining room and thus need to alter the threshold between the rooms). We just saved thousands of dollars b/c we had extra floor tile for one of our bathrooms (the tub had to be jacked up - wasn't level, thus leaked - and thus the row of floor tile abuting it replaced).

But, I'm not a fan of any accents or feature wall/tile sections (and no one should take design advice from me!), so I'm no help!

I was going to say the same thing. Save it. You never know when you'll need to patch something up, or when you'll want to carry that bit of extra tile to the store to help you pick a new paint color.

I store my extra tiles in a too-high cabinet over the refrigerator.

Depends on how many you have left. If a handful, I'd keep them for possible repairs. If more than a repair supply, I'd return for credit. If past credit period, I'd sell on CL or donate to habitat.

HST, i had a stack of bricks that I kept for over 20 years and my husband recently used for this curved half wall. We had a convenient space for it,

We decided to keep any extras just incase. Thanks everyone!

We gutted 4 bathrooms in the last 2 years and I am storing way too much extra tile for "just in case"! I should go through it and figure out exactly how much I should really keep. Luckily we do have the space to store it, but it does take up room and is heavy/bulky if you need to move it for any reason.