To expand on what the others have already said, I will give a rundown of some other choices than just Relthoza.
The Relthoza are an obvious choice. Nearly all their tier 1 options can bring (or be upgraded to bring) 6+ SRS. The have two tier 2 choices that can bring SRS, although shunt cruisers are only WC 1, and assault cruisers have to bring assault boats. They are, as stated earlier, they only faction with a tier 3 model with WC. They have a TAC to bring back lost SRS wings. The Zenian League has a TAC that can allow your SRS tokens to not be driven off during the turn it's played, at the expense of being forced to lose 1 wing.
Aquans are another obvious choice for an SRS fleet. Nearly all their tier 1 options can bring (or be upgraded to bring) 6+ SRS. They are about to get some cruiser-carriers. They have a TAC that prevents the destruction of any of their SRS during the turn(s) it's played. They have access to a decent amount of models with Precision Strike to make targeted strikes they perform more likely to successfully knock out PD systems on models you're going to hit with SRS. They have a TAC that makes targeted strikes much easier with models with Precision Strike.
Dindrenzi have a super wicked assault carrier. They are about to have some (hopefully, super wicked) cruiser-carriers. Combined this with their powerful weapons, I believe Dindrenzi SRS lists will become a solid choice after the Task Force release. Their carriers can have Deck Crews (this can rebuild lost SRS). Dindrenzi have the RSN as a natural ally. The RSN have a really nice carrier, that can also have Deck Crews. The Zenian League has a TAC that can allow your SRS tokens to not be driven off during the turn it's played, at the expense of being forced to lose 1 wing.
The Directorate have a carrier, an assault carrier, soon some cruiser-carriers, and are natural allies with Works Raptor, who whave an assault carrier and battlecruisers that can be upgraded to have 3 WC apiece. Their carrier is a great cloaked cyberweapon platform of doom. Both theirs and WR's assault carriers are fast, somewhat durable, and able to deploy SRS in the face of the enemy while themselves assaulting models. The Directorate also has access to the highest amount of cyberwarfare in the game (so far) that can be used to disable the PD systems of enemy models you wish to hit with SRS. They also have a TAC that gives every targeted strike made during the turn it's played a chance to ignore the -1 to hit, allowing them more chances to disable PD systems before striking with SRS. The Directorate are also natural allies with OSO Omnidyne, who have a dreadnought and battleship that have a WC of 4-12 and 0-6 respectively. OSO Omnidyne has the second highest amount of cyberwarfare weapons in the game (so far). The Zenian League has a TAC that can allow your SRS tokens to not be driven off during the turn it's played, at the expense of being forced to lose 1 wing. NOTE: Without using Commander Olga, you cannot bring OSO Omnidyne and Works Raptor in the same fleet. NOTE: Bringing OSO Omnidyne models at all restricts you to the general TACs only.
Terrans have two carriers. One can have a WC of 12 and comes with Deck Crews. The other can be difficult to kill. A Terran carrier list can play with defensive / support SRS and use it's (primarily tier 2/3) torpedo volleys at longer ranges to whittle enemies down until it's time to engage up close and deploy offensive SRS. Terrans are natural allies with Hawker Industries, who have a relatively tough carrier with built in Deck Crews and the potential for cyberwarfare. The Terran defense platforms have WC 6 (with 3 of them). While they are immobile, they are cheap, and a tier 2 slot, and great for scenarios like Ambush (attacker), Capture the station (defender), and the planetary invasion scenarios (most of these require the defender to take these).
The last faction I will speak about is the Pathogen. All their tier 1 ships have a WC. Every tier 1 ship the capture has a WC. Their wings are better than everyone else's wings, but cost 10 points each instead of 5. Winning dogfights and killing enemy SRS rebuilds their SRS. Their SRS can assault and capture enemy models (just like assaulter SRS for everyone else) and add that ship to their carrier's squadron. As a Marauder fleet they have a TAC that shuts off a models PD, guaranteed. They have a TAC to cause an enemy squadron to make a disorder test. Being disordered, among other things, prevents that squadron from launching SRS, and forces any launched SRS to immediately return to base. This can be used to great effect to get an interceptor token out of the way, or keep offensive SRS from attacking you.
Other than these factions, nearly every faction has some kind of WC. These are just the ones that I personally believe to stand out as being super capable at achieving what I believe your goal to be.
A big thing to consider when making a fleet where you want SRS to be your primary weapon is to remember that SRS can be shut down by interceptors. Bringing your own fighters to dogfight enemy interceptors before bombers/assaulters are used is almost imperative. Also remember that SRS are absolutely amazing, until your opponent rolls a couple 6's on PD rolls and you lose some. A Relthoza player with 4 fighters on a Nidus frigate squadis happy. A Relthoza player with 2 fighters on a Nidus frigate squad is significantly less happy. Also, while SRS are a wonderful tool, they should never be the only one in the box.