I'm not quite clear on what you are asking us for.
You want "easy imslp music fast"? Well, thousands upon thousands of public-domain scores are there for the taking - just go to
https://www.imslp.org, and you'll find it all there. You can print out whatever you like, and then play it.
Easy? Well, I don't know how easy you mean - but there are various ranges of difficulty in the music there. You just need to look and see what you can find.
Ideas on how to learn sight-reading *fast*? Well, I don't know how fast you want, and I also don't know how fast is possible. But you'd better just get to a piano quick-smart and start sight-reading without any delay if you are really in a hurry - that's the way to get good, although it won't be miraculously fast, unless you are a true genius.
I am told by various people that I am very good at sight-reading, so I suppose it could be true. (I have almost no musical friends or even acquaintances, so I really have no-one to compare my own accomplishments with.) And I did it by decades of playing over piles of second-hand music I got into the habit of buying, which I wanted to explore. I suggest you get as much music as you can, whether from web sites like I.M.S.L.P., or from book-shops that sell second-hand music, and play through it. Choose many different styles, and stretch yourself by including music that is beyond your formal level of playing. I tackled Scriabin Sonatas and Szymanowksi Sonatas at one point - at other times Chopin, Beethoven, Debussy, Rachmaninov, Prokofiev, John Ireland, Cyril Scott, William Baines, Frank Bridge (I always loved those British composers) even in the 1970s, way beyond my "formal" ability - but they fascinated me so much I just wanted to find out how they were constructed. Also did Scott Joplin, Dave Brubeck, and music of that sort, too - Billy Mayerl rather more recently.
I never set out to learn Scriabin's 7th Piano Sonata - but around 1980 or so I somehow became obsessed with it, and played over parts of it on the piano for hours on end, without ever really intending to learn it (fully believing it was way beyond me), just because I somehow had it on my brain and wanted to hear its melodies and harmonies yet again - but I did almost become capable of playing significant chunks of it, and I got used to playing the complex rhythms and the jungles of accidentals before each chord. Even if I never intended learning such music *properly*, these efforts to stumble through music way beyond my technical ability did, I believe, at least help me develop my sight-reading skills.
You might like to try a similar thing. I don't know how quickly this would develop your sight-reading skill; but I am sure it would do so at least quicker than if you didn't stretch yourself in these ways.
If you are interested and able to, you might also like to try composing your own music. I believe constructing one's own music probably also helps, in a different way, to build up musical understanding and fluency with music notation - and that can also (maybe) help your sight-reading ability.
But there's no magical secret (that I'm aware of, at least) that, once given to you by one of the gurus here, will automatically give a huge boost to your sight-reading ability.
I hope this helps a little, although I'm not entirely sure it will: something about the way you wrote did have a bit of a feel to it of asking for the impossible.
Regards, Michael.
Topic: I need to get good at sightreading FAST!