I love making salad dressings from scratch, and also love eating hummus but I make very small amounts of these things. I also plan to move soon and will be donating most of my kitchen stuff when I do, so I’d like something that could be well loved by a new owner. Is there anything out there that fits the bill? Or even better something I might already have that fits the bill? I don’t have a blender, either. Already donated that one.
Consider a Magic Bullet! Or something similar - there are a bunch of small blenders out there designed for single-portion smoothies that fall in the $20-$40 range.
Some immersion blenders come with replaceable toolheads too, including a more traditional food processor style. I got a replaceable toolhead model, but no other attachments. Haven't needed it. I got it for soups in my slow cooker, works well.
Edit: I think I might have seen that some blenders come with food processor attachments too? Don't have one of those.
I forget what it's called right now, but the 3.5 cup KitchenAid food processor gets a lot of use here. I generally don't like to use food processors just because they're so loud, but this one isn't too bad. It's quick! But it is small, so it has limited uses.
I would get that plus a cheap immersion blender. That'll cover basically all of your needs for what you're talking about.