They don't hybridise as far as I know, or don't give anything long-lived.

An interesting hybrid though is x Sorbopyrus, a cross between a pear and sorb tree.

There are some apple-pear hybrids that produce fruit. Development work seems ongoing in Germany. Unfortunately for me as (mostly) an English speaker, most of the papers describing it are in German. Here's a summary of an abstract in English, though: https://agris.fao.org/agris-search/search.do?recordID=US2014.... If you search for the primary author plus some keywords (Thilo Fischer Apfel Birne) you can find articles that give more details.

I'm guessing the Sorbopyrus you are describing is the Shipova: https://en.wikipedia.org/wiki/Shipova. It's a surprisingly old hybrid. I've got one growing, but haven't gotten any fruit yet. Have you eaten it?

I have never eaten it, but it's at the top of my list of trees to grow once I have enough space for it.

Never heard of it so for others https://en.wikipedia.org/wiki/Shipova

Can't cross with an apple but can with a whitebeam, I wouldn't have believed it. Amazing, thanks.

Not that knowledgeable. We just wanted to plant a pear tree when our kid was born. The tree seller was very chatty and knowledgeable.

You also need to plant pears in pairs in order for them to pollinate each other. There are tables with which varieties go well with each other.

If you can, try comice. A diva to culture, but the fruit is fantastic.

Pears are not the easiest fruit to culture and in some areas is a doomed project from the start. --Don't-- buy trees in the supermarket without a sanitary tag. Go to a professional. Fireblight is a real pain

apple and pear don't hybridize. They don't even can be grafted one in the other. The tissues are rejected. There are round species of pears naturally shaped as an apple but they are not "pears" (common pears) neither apples. Are from Japan and are called nashis or sand pears. Tasty and crunchy, very good in salads

Pear and quince can hybridize producing a fruit called Pyronia (= Pyrus x Cydonia). Is not better than any of the parents, so it remains basically unknown and unavailable.

Quince is able to hybridize with apples and pears.

https://cornusmas.eu/catalogue/intergeneric-hybrids

has some information about some interesting mixes (and he sends out great plants if you are in Europe).

Palms also form fascinating hybrids and there is an active community of people around the world doing this and sharing information.

If anyone interested I stumbled on this https://www.agroforestry.co.uk/wp-content/uploads/site-files... "Rosaceae family intergeneric hybrids" which covers a number including those mentioned here, plus hawthorn, medlar and rowan mashups