Let me explain.
I have a pdf of Magnolia's and Ash's 'Here Be Dragons' with a bunch of dragon types and their invocations in case you want to bring them in. There are multiple cool sounding dragon species I want to summon,but I don't really have much of a reason to do it than for mom to just describe to me on what they look like so I know if they're in the house.
When you summon spirits, I think you're supposed to ask them to do something. Problem is that I do almost all of my magic myself (except today my secretary bird familiar "F" and my Dark phoenix "S" is sitting beside a long red glass candle taking care of an issue that I can't do myself.) and I don't really have a reason to summon dragons into my house.
When I do try to summon a spirit, I try to leave them something on the counter for them to pick on and hope mom sees the spirit that might be in the room since I can't see them. That's how I ended up meeting 'S' before I had a custom conjuration done.
Anyway, I want to meet different types of dragon spirits but I don't have a reason for them to be in my house...what should I do?

Just a personal opinion but I'd do it and just be humble about like "thanks for coming how's your day going" anything interesting happen today? "

I feel like a reason you may be overlooking would be to just meet with them. Sometimes there's no other reason then to just have a chat with one of those dragons. As suggested above, just talk with them. Indulge them in conversation. I'm not sure how rude this would be - just to summon them to see if you can, and then let them leave - so I think you need to figure out how to occupy their time to be worthwhile.

A suggestion I might have is to indulge them in a conversation or talk to them, tell them a story, tell them hopes and dreams, talk to them. That's a way to give them an offering for their time to even come to you. Or to give them some sort of food offering, or incense offering - just something to offer them. Or else it's like telling a stranger "Hey come inside, I want to look at what you have", and then telling them to get out of your house without any further interaction. Personally, to me, that sounds very rude and I'd probably get offended and decline. Dragon's are very distinct creatures, and I don't think you'd want to offend a dragon if you could help it. Being humbled and honest is definitely a way to go, too. :)

I don't kick spirits out when they appear. If they feel like staying then it's fine but if they don't, that's fine too. Like I said, I just leave them a food offering or whatnot and hope they take it since just bringing them in without doing anything in return is rude.

With the caveat that I would always myself stick to the precise instructions given, eg whatever the precise summoning process in that book is and whatever it may say about the need for a reason (if it does)...beyond all of that there are loads of items in the CH shop that enable us to safely summon spirits just for contact and interaction.

So it's fine to not have a 'worthy' reason on top of that. Wanting to get to know different types of spirit is itself a fine reason to go ahead and do that (using a safe, reliable method), in my opinion.

Dragons (most) are considered white arts so they may not be offended by your curiosity. And you have safe invocations from a knowledgeable practitioner so I wouldn't think that's a problem.

However, generally speaking, i would exercise caution in doing this with anything considered gray or dark arts (including such dragons, like black dragons). These are spirits of the dead and some do not take kindly to curious people playing at summoning.

I know some who would say do not disturb the dead without cause. It's not something to play with lightly.