Hi, few hours ago I have just built my first lego set LEGO Ideas 21309 NASA Apollo
Saturn V it was an amazing experience. I would like to build next, please can
you suggest me some good lego set? Number of pcs 1500 and more and I would like
space theme but When I was searching I did not found anything space themed like
NASA Apollo Saturn. Im not big fan of star wars series but maybe it would be
okay too. Thank you for every suggestion.

21311 Voltron

https://www.amazon.com/LEGO-6207485-Voltron-Building-Multicolor/dp/B07D4BWZ3T/ref=sr_1_1?hvadid=256451902448&hvdev=c&hvlocphy=9003819&hvnetw=g&hvpos=1t2&hvqmt=e&hvrand=11985587154005091686&hvtargid=kwd-345554808867&keywords=lego+voltron&qid=1555791047&s=gateway&sr=8-1

 

London Bus 10258

I have done some research and I have decided that I want to specify on one theme. I really like harry potter legos because it is my favourite film and architectonic is good too. Which category is better in your opinion and what sets are good for start in theese categories? I like bigger sets. 

On the other hand I found this lego set LEGO 10253 for 220€ it seems really good price but it is not architectonic, it is creator. 

It looks like there is going to be a space theme in the City line, along with a space people pack.  You may want to wait, so check out the leaks on those.

I don't like architecture sets for the build, the finished product is usually nice, but it can be tedious to get through the builds.  They tend to be repetitive, and while I haven't built Big Ben, it looks like a chore.  If you go the architecture route, pick a finished model that you really like the looks of.