Taggiasca olives. These black were billed as 'classic Italian olives in sunflower oil and olive oil with oregano' which sounds lovely, but actually they are quite foul. They have huge stones, and their thin flesh is sort of flabby in texture, with a nasty aftertaste. Strong suspicion that these are the dregs of the Italian crop dressed up posh for the British market.
Picholine Olives - green French olives, stone in. These are pleasingly crunchy, with little stones and lots of flesh with a nice smooth rich flavour and not much aftertaste.
Crespo pitted green olives in brine - what I think of as as a standard olive. Bit of a crunch to it, nice and salty, handy they are pitted so you can chop them.
Crespo pitted black olives in brine - I thought I didn't like black olives as much as green ones, but actually these are really nice, they have a nice rounded fruitiness to them.
Waitrose Spanish pitted green queen olives - These are very large and have a good crunch to them - nice olives to add to a salad, but I felt they didn't have quite as much flavour as the Picholine French olives.
Greek Kalamata black olives (in brine and wine vinegar). These are very different. No crunch at all, an almost meaty combination of rich flavour and squishy texture, and a strong aftertaste. Similar in some ways to the Taggiasca olives I didn't like, but with more interest to them. I'm not sure I'd like to eat a *lot* of these, but one or two among other olives makes a fascinating contrast. I suspect they'd be good as a flavouring too.
Large green olives stuffed with garlic - these may be my favorite so far. The olive has a crunch, the garlic has a different crunch, the flavours work together really nicely. From a small delicatessen in Tavistock, so no further info on origin, and they were relatively expensive so don't really fit the 'buy a big jar' model.
Cracked green Spanish olives - large, salty, stone-in. Not much crunch, though they definitely have more solidity to them than the Kalamata olives, for example. Quite a strong olive flavour. You wouldn't want to eat piles of them, but one or two are very pleasant. Not sure what the point of the cracking is, they just look slightly bruised. Also from the small delicatessen in Tavistock.