You know years ago, people 'made do' with cameras that had just a fixed angle of view, equivalent to something like 20 to 35mm on APS-C widgetal.... The 'trick' was in recognizing what you could and couldn't do with it, and working with what you got, rather, than is modern precept, expecting to be able to just buy a gadget to do it for you....
I need to know what size lens i need to take pic of deers
Deer, no need to pluralise that BTW, are not exactly small creatures, you can fill the frame with one quite happily with a 'normal' angle lens, like the one you have....
Of course, you have to be reasonably close to do that, and wild deer are often flighty beasts... so anything longer than 50mm may make filling the frame with venison a little less challenging, BUT, the 'skill' is still in the stalking. If you dont have the patience to stalk or set up in a hide, and wait for deer to come to you; or the perseverance & dedication to get up early in the morning when the deer do and start to forage, then you are starting from behind, and as said, no lens will do the job for you.
Birds are usually rather smaller quarry; to get frame filling with a finch, even at suburban garden ranges, you will struggle with much under 200mm. BUT they are also quite flighty, and with the very arrow angle of view of a long lens, actually scanning the scene to get the subject in the frame, and holding them there is often rather challenging. Still, stalking skills apply, and the gadgets wont do the work for you.
A-N-D more, long lenses often bring more problems than they solve; starting with that scene scanning niggle, then progressing through the matter of magnifying camera shake, which begs more diligence and discipline from you in your stalking and holding, before moving on to them making focus that much more critical, whilst often having more compromised apertures. So again, you REALLY need to have the know-how, NOT a long lens. If you don't have the know how you wont get results with anything If you have the know-how, you can get results almost with anything, and will either know when you might get better results with a longer lens, or simply it's going to make more work for you,
More Land does not more Landscape make. Wide angle lenses are as tricky, if not more tricky to get to grips with as tele's. Tele's are a bit of a one trick dog; with such a narrow field of view, they cut clutter and add impact, simply by only leaving enough space in the frame for the subject, to focus the viewers attention on. Wide angle's pack in a lot of real estate & in doing, tend to shrink the prominence of any feature subject, and include an awful lot of incidental 'clutter' detracting from that subject. Actually exploiting a wide angle to capture a dramatic scene and retain 'impact' is something that is very hard to do, and in the 'eye' not the lens. Worth noting that most of the 'great' Landscapes were taken, actally NOT with a wide agle lens, but one close to the 'normal' FoV, which is around 35mm on APS-C... slap bang in the middle of your 18-55, which is a damnably useful lens for the job. That mild tele end, is also quite well worth playing with for landscapes, cutting the clutter and focusing attention on a smaller 'section' of scene.
pics of family members with blurry back grounds
Blurry Backgrounds? Yeah! Shallow Depth of Focus then.. complicated topic this, I have been pondering a tutoral on; BUT as other comments, what you got and 'know-how' will do this job admirably. Common conception you 'have' to have a fast aperture lens, is sorry, 'tosh', and again, unless you have the know-how, likely to make more problems than it solves.
Issue is one of 'Selective Focus' rather than mere 'Shallow Focus', which is what fast apertures deliver, and which actually may NOT be what you want... sure it can chuck near back-ground 'oof' pretty easily, but such skiny Depth of Field can just as quickly see ears and noses going bury with the back-ground! Conversely, you can get some pretty effective blurry back-grounds, and keep noses and ears in sharp focus, with pretty 'slow' and relatively 'wide' lenses; in my tutorial musing, I was actually playing with a 29mm 'prime' at f4 and f8, and getting dissociated back-ground effect 'portrait' shots with it, and a little know-how... MOSTLY turning the Auto-Focus 'OFF', and putting the Depth of Field where I wanted it around my subject, not where the camera 'defaults' to put it, 1/3 infront and 2/3 behind whatever the red dot ranges in on... if you go manual, you can focus 'infront' of your subject, pulling the back of the DoF zone forwards, so your subject nose and ears an'all stays in it, but, back-ground goes 'oof' that much earlier; again, takes that bit of know-how, and some discipline and patience; you wont get that 'effect' very reliably with turbo tearaways tearing about the park; either with a fast prime or long zoom, and shallow DoF placed arbitrarily by the red-dot! Not so likely going manual and 'Zone Focusing' either.. but that little t of know how and discipline you stand a better chance!
Conclusion then, is REALLY, what you have got already, is as much camera as we ever could dream of in years gone past. It has every film in the shop in its huge range of ISO settings; whilst it's 'moderate' zoom range, covers the most used range from what was pretty 'wide' to 'quite' telephoto, and far 'more' versatile than cameras of old, when we had to work with a fixed 50mm pime or maybe a 35-70 'zoom'. AND it has all the advances and advantages of SO many easements and automation, from automatic exposure, through auto focus, BUT, for all that automation it STILL wont do the job for you, YOU still have to take the photo, ad work woth what you got to get it.
IF you expect a wider lens to get you 'better' landscapes; if you expect a long tele to get you 'better' wildlife; if you expect a faster lens to get you 'better' people shots.... you are likely to be quite significantly disapointed as well as out of pocket; the gear will NOT do the work for you, and likelihood is that it will demand MORE work from you to get what you want with it, ad if you aren't puttig that work in to get the results you want with the kit 18-55, you wont put it in with a UWA long tele or fast prime, ad will likely get worse results than you do now.
Better Photographers take better Pictures, NOT better cameras...... get a better photographer behind the lens. Do some home-work. Get some know-how; Practice & Patience, Diligence & Discipline, and yo'll get far more, far easier and cheaper than cracking out the credit card ad filling the bag with gadgets that still WONT do it for you. Lear the lesson of the masters of old.. WORK WITH WHAT YOU GOT! You already have far more than most of them ever did!
What camera do you use, as for wildlife lens would have to start at about 300mm.