Seachem makes an extensive line of plant fertilizers. You can view their full line here. They also have a ton more information than what you will find below including product FAQs and dosing.
Flourish - This is comprehensive planted tank supplement. It includes micro elements, trace elements, and other nutrients that plants need to thrive. Flourish is invertebrate safe, so feel free to dose it into your planted shrimp tanks. Note: A 100 mL bottle will treat a 40 gallon tank for about 4 to 6 months.
Flourish Excel - Couple this with Flourish and your plants will be thriving. Excel is a bioavailable source of carbon for the plants in your tank. There is a lot more science behind this than meets the eye, if you are interested they explain it one their website. Excel is safe to use on planted tanks with invertebrates. Note: A 100 mL bottle will treat a 20 gallon tank for about 1 to 2 months. Dose only the recommended amount and keep away from kids, non-aquatic pets, and irresponsible adults.
Flourish Potassium - Potassium is probably the most rapidly depleted elements in a planted tank. If your tank has rapid plant growth, it is possible that your potassium is being depleted. What's the easiest way to tell? If your older plant leaves are beginning to yellow it could be a sign of potassium deficiency. Note: A 250 mL bottle will treat 50 gallons for 4 to 6 months.
Flourish Iron - Iron is essential to all plants in your aquarium, but especially if you have plants with red leaves. If you notice your red plants are beginning to turn green and want to return them to their former glory, you should be dosing iron. Other plants can be iron deficient as well. You can see this in the new growth of plants. If there is yellowing and/or short slender stems on the new growth of plants you might have an iron deficiency. Note: A 250 mL bottle treats a 50 gallon tank for about 4 to 6 months.
Flourish Advance - Advance is a natural phytohormone supplement for plants. We usually recommend dosing this stuff in addition to Flourish and Excel when trying to establish your plants. This works exceedingly well at getting plants to establish root growth in the first couple weeks. You can continue dosing after that for increase leaf growth as well. Note: A 250 mL bottle treats 1,000 gallons. You will probably be dosing this daily for the first two weeks, so buy a bottle that corresponds to this.
Flourish Tabs - Tabs are a substrate supplement for tanks with passive substrates (sand, gravel, etc). We recommend using tabs when you have high demand root plants such as Amazon Swords, Tiger Lotus, or even Crypts. Note: A ten tab bag will treat 20 gallon tank for about 4 to 6 months. If you are not planting your entire tank just put these guys near the plants to save some money.
Flourish Glue - This is exactly what is sounds like. You can use this stuff to glue mosses, Java Fern, Anubias, etc on to rock or driftwood. This stuff dries underwater! Note: Keep this glue away from kids, pets, and irresponsible adults. You can glue yourself to yourself with this.