The first rule with gene banks is to make sure that you have exhausted your other options first before using one. I happen to know there is some promising available habrochaites genetics just in Joseph’s Neandermato strain alone for cold hardiness breeding. Also, starting there would be helpful for getting used to working with habrochaites which is a long slog.
There are several gene banks around each has different rules, but several have good tomato collections. TGRC might not be the best of those to approach as TGRC told me that I must be affiliated with a university or gene bank to request any more seed. Before that they did send me five accessions. I think as plant breeding becomes more popular they are becoming more protective of these resources. I think it would make the most sense to have a university researcher who was willing to manage some citizen science with tomatoes that we could consolidate our requests through or somehow organize a new or existing gene bank like the seed savers exchange that we could do the same with. It would be great if they would also manage and redistribute seed that has already been made available to the community. I think also it might be worthwhile to occasionally self-reflect and consider if you might be so interested in plant breeding that a graduate degree in it might be desirable. If a person ever found themselves in that position, they would certainly have a university affiliation for a few years at least.
Another note about TGRC they have a materials transfer agreement. Tomato Genetics Resource Center - Material Transfer Agreement
To be honest I don’t fully understand the MTA other than that any TGRC materials are bound by it and anyone you share seed with of them you should ask if they are ok with it before sending those seeds. I think it is pretty mild in many ways and simply seeks to shield the UC from any liability. Though there is one worrying sentence about commercial usage requiring contacting the UC regents- I kind of interpret that to mean, give the seeds away only and only accompanied by the MTA or after confirmation that the receiving part is ok with it. That is what I do with the accessions I have and those TGRC accessions I received from another independent breeder. I would have to say I would prefer a source that doesn’t ask for an MTA of any kind. I would love to have someone with a bit of legal background explain it better to me.
Also, a note on how many accessions a breeder can effectively work with- Maybe as few as a single accession. You might find that if you bought everything available from HRseeds, J&Lgardens, and EFN that you were completely overwhelmed with wild tomato material for breeding experiments. I know I am already. An independent plant breeding colleague of mine requested so much and shared it with me that it feels like a burden to grow it out for seed increase and share it- which I recently did with an organization I hope will find a way to share it but it may take them a few years to seed increase some of it themselves. I plan to keep sharing it as well with that same organization and with anyone who says they are ok with the MTA but I cannot share it internationally personally.
Another note: accessions vary from easy to almost impossible for an independent breeder to work with. If you can get some commercial material for a tomato species and work with it a few years before requesting an accession, you will be much better prepared to actually accomplish something with that resource.
So those are the reasons why I did not mention TGRC or ARS-GRIN or IPK. I do not recommend them as a first source. Only after growing a species already for three years, making a cross with it, maybe developing some plant tissue culture and embryo rescue skills for the difficult species.
If you do make a request to a gene bank- please consider doing seed increase, ideally before making crosses, and sharing it with the community of independent breeders so others won’t request that same accession repeatedly. There is a good tradition of this and you will note that if you go to say Victory Seeds website that many heirloom tomatoes were rescued from seed banks. Take the following for the heirloom Magnus:
“Through the efforts of Craig LeHoullier and Carolyn Male, they located seed, accession number NSL 27381, stored within the National Seed Storage Lab in 1994.”- Victory Seeds
I think it should be the same for many wild accessions. There are just fewer of us willing to cultivate and breed with them to support it.