Any good 5 stars to save for?

Jalter should have a banner sometime in the next few months. Theres also Musashi not long after Merlin I think? I know theres a list of banners you can expect somewhere. I'm sorry I dont have the link off the top of my head but it should be easy enough to find

As far as I can see, you lack a good ST lancer and Archer, lucky for you, in the Summer banner that will come in a few days, there will be 5* servants of those classes, Tamamo Lancer and Arturia Archer, both are top tiers as servants even on JP, so if you had saved a good amont of quarts you may be able to pull for any of them, also ote that they are limited, and are rarely seen after their event, so try for them is my advice. :D

We have a fair amount of new SSR units releasing this year still.
Of course the summer units coming very soon feature the ever powerful Archer Artoria, may be a little too late to save for her at this point though.

Illyasviel has her debut along side MedB in the coming weeks as well, cute units but not exactly game breaking.

Bride Nero see's her Rerun along with the new Nerofest unit after that, an excellent unit for art teams and just good all around.

Jeanne D'Arc Alter also gets her rerun banner shortly after, a powerful and fan favorite Buster Crit oriented unit who you may see perform well with your Jack or Kintoki(Rider).

Tamamo no Mae gets a rerun for Halloween as well, an excellent pick up for anyone interested in Art teams, would be nice for your Shiki, Nursery Rhyme, or make a powerful supporting setup between her and Waver to allow you to pick a strong support lineup DPS unit for an arts team.

Cleopatra debuts next on the second Halloween banner, she is a serviceable AoE Assassin with the unique danganronpa art-style just like Dantes. Some people like that, some people dont and how you feel about a servant should be the biggest factor in pulling for them. She releases along side the SR Vlad Lancer who is a very nice unit to pick up along the way trying to get her.

Next we hit the big boy banners for Christmas and Babylon, first up is Ishtar for the new Christmas event most likely starring in November. She is an incredibly strong Buster Archer who also features the appearance of fan favorite Tohsaka Rin. While she debuts on Christmas, she also gets a rerun for New Years which features a much more interesting Craft Essence for her so if you want to pull for her it might be worth waiting the extra month.

Enkidu releases shortly after her and is a neat and versatile Single Target Lancer with a very clean art style. He also features the SR Gilgamesh on his banner who also a really good unit.
Quetzalcoatl stars on the second Babylon banner, she is an incredibly strong Rider with good damage and team support capabilities. Worth noting she also features Gorgon a SR Avenger on her banner which is a nice pickup to complete class advantages.

The last banner of the year features everyone's favorite broken wizard Merlin. Should not have to explain how dumb this unit is and how he has shaped the meta everyday since his release. Worth noting though that everyone and their mom will be pulling for him and if you feel comfortable just taking a support Merlin then skipping his banner is a very plausible idea. While Double Merlin is a common meme, there is no real good reason to specifically want it.

However we also get the New Years banner featuring a whole cast of Limited or Rare Servants, and the debut of Musashi. Musashi is a very very powerful Buster Saber, who works extremely well with the just released Merlin. Musashi may even be as common to see in challenge quest videos as Merlin due to how strong they are when combined. The banner also features rate-up days for Gilgamesh, Ishtar, Shiki Saber, Scathach Kintoki, Illyasviel, and Iskandar. Very nice lineup featuring some of the strongest servants for specific roles in the game, and features a very nice Craft Essence on the side called First Sunrise which has Buster+, combined with Starting NP Bar. A nice item to have for pretty much everyone on the banner should you choose to roll on it.

Worth noting shortly into next year is also the debut of King Hassan, a very powerful Assassin that while provides less utility as Jack does with her stars provides damage on par with hers without relying on special tag advantage.

As always I still recommend just going and checking out some art for the characters and seeing who you think looks appealing and you would be happy to see used on your team, unless of course you just enjoy owning units and knowing they are better than others in which case you would probably save for Merlin, Musashi, or Gilgamesh anyway.

you're not going to summon a 5* by saving up and spending it all at once
there are players who whale to get 5* but fail miserably the reason is gacha has periods of good and bad rolls predetermined for each player
I summon whenever I can and so far (4months) I deduced this because seeing players that save up and summon and not get ssr's for months at a time while me getting 5 ssr's in 2 months (and a few 5star CE)doesn't feel like a Quincidence.
you either get it or you don't
edit; for the record it is technically 4 ssr's one of them being np2 iskandar