It is that time of the year to start ordering seed catalogs. There are national seed companies of course; such as Gurney's and Burpee. I have ordered seeds from both and was completely satisfied with them. But you should also do Internet searches for local seed and plant companies/nurseries. It is always better to buy seeds/plants that are grown in your local area. This more or less ensures that the plants will thrive in your growing zone.
If you eventually want to save your own seeds, for more assured availability and self-sufficiency, then you should look for "open pollinated" seeds. Only open pollinated seeds grow plants from which you can save seeds and the seeds will produce plants true to form. The other main stream seed companies sell mostly hybrid seeds. You cannot save seeds from hybrid plants and then expect to grow plants from them the next year. Because they are hybrids, you never know if they will germinate or what will grow from them if they do sprout. Do an Internet search with the term "Open Pollinated Seed Companies" and you will get quite a few hits.
Johnny's is one company I intend to check out this year. They sell forage seed (amongst a lot of other products) and I have cleared a 20-30 foot edge around one of my fields and want to seed it for wildlife food plots. Because I have been an absentee land owner for 30 years, brush and trees have been encroaching on all my farm fields. This winter I have been pulling out the brush and small trees as well as cutting back over-hanging branches. It has been a lot of work but I owe it to my tenent farmer to free up more cultivatable land. I will maintain a food plot ring around each of my fields as I clear them. This will support more wildlife and make it easier to cultivate the fields.
Seed catalogs generally also contain planting, growing, and harvesting tools and supplies. None of them are needed, but many of them will save you time, make your work easier, and extend the growing season. The catalogs will also give you ideas of new crops to try out and the descriptions will help you select the right seeds for your growing plan. If you do intensive gardening with successive crops, you will need to select early and late ripening versions of the crops you want to grow. Just keep in mind, the catalogs are designed to sell their product so do your research before buying.