In need of a archer

You missed Gilgamesh & Ishtar, if you didn't roll during thanks giving or Christmas. That said they're both back for the new year's banner.

Good Archer? Well, Emiya is good if you have right CE and make good team for him (star abortion for instance, and have critical team with star generator)

Nobunaga will be free welfare next year, but imo her function is almost closed to Emiya. Off course either has own superiority and drawback but quite close.
Also free Altera, but quite late for 2019.

Meanwhile Euryale, Robin and David are 3-star archer but all functioned great.

Overall, the best way to obtain good Archer is to roll GSSR in new year. it guarantee you will have a non-limited SSR archer. Although these 3 ssr Archers (Orion, Tesla and Arjuna) are not quite OP as Gil, but still deserved for investment.

GIl and Ishtar will be specific limited banner next year, but they required your whaling normally.
Tomoe is also great as SR

Okay so generally all Archers are good. Even 3 stars like I mentioned.

Gilgamesh is the best archer in the game, especially if you are fighting servants. every servant that is not of the star attribute will take extra damage from Enuma Elish. You just missed his banner, so he won't be showing up any time soon.
Artoria is also a very good archer, she can do obscene things, like fire 2 nps back to back if you give her a support tamamo or waver. But she won't show up again until summer rerun.
From lower rarity servants raise your euryale she hits like a truck against male sabers/berserker .

You missed Chloe (she still no re-run), Artoria Archer(she will have pick up event on re-run in July), and Ishtar (maybe have pickup event on new year).

Most of archer in NA currently have bad np gain with exception of Artoria and Chloe. I don't have Ishtar so no comment on her. Just for recommendation some good archer that available in NA

Atalante - her NP is one of the best star generating NP. in JP she gain success after Scathach-Skadi arrive.
Euryale - One of the best Male killer in game. her NP gain is on low side but can be covered by vampirism skill and support just like Robin. her np deal more damage to male saber and berserker than robin
Arash - He's a god in farming after strenghtening. if you have kaleidescope you can clear 1st wave easily with him
Oda Nobunaga - you can get her during Honnoji rerun in late feb or early march. an anti divine/riding AOE saber/berserker
Nikola Tesla - don't have him but he good as farming servant
Arjuna - I heard people say he suck
Billy - he's a one turn crit burst damage dealer
Tristan - he can make quite good amount of crit star + his team evade skill is useful
Anne Bonny/Mary Reed - they are crit archer that works differently than normal. their NP gain extra damage based on how low their hp is. hard to use
Orion - the goddess Artemis kidnap him and curse him into a doll. She an anti male servant with charge draining NP. works well in art team
Artoria Archer - Best archer currently. she can basically said "Swimming no Jikan da" almost everytime. she had fast np gain with her NP has chances to drain NP + NP uptime.
Chloe/Kuroe - Second only to Artoria but you will have no chance to get her since still no rerun on Prisma Code in JP

Some future Archer you might want :-

James Moriarty - the prof is a single target crit archer. but his NP battery need to be paid in crit star.
Emiya Alter - JP said he become quite a beast like his OG form after strengthening
Tomoe Gozen - honourably mentioned during Babylon chapter, this widow is a crit offense archer that support the the with star generation buff and atk buff only to steal the star for herself.
Altera the san(ta) - free servant during Christmas next year. single target quick archer with NP that supply stars.

Gilgamesh is pretty much considered best archer in JP at this point. Ishtar is another good AOE option, both are available next year.

As for ST, best is probably summer Altria, she's available in the summer 2018 rerun next year, though that happens right before summer 2019 which also has some pretty great servants in it, so it might be a bit of a hard choice to roll for. If you are at a loss for that one, Orion is also pretty good, he's available very early next year on rate-up during the moon festival event.

ST= Archuria(Summer Artoria)
AOE= Gilgamesh
I'm gonna aim for these two. They're pretty good. And cool. Waifu/husbando