What sort of tissues? We have used FTA cards for blood and some other soft tissues, ethanol for muscle plugs or fin clips, and have gotten high molecular-weight, high-yield DNA suitable for WGS from dried tissues, and others have been stored at -80 C with no other preservation. For whole soft bodied organisms (e.g. small flatworms) we have tried both dried (in small plastic bags) and fixed to FTA cards and found no difference in yield. For leaves we dry them with silica beads and freeze. We have even had some luck from snake sheds and road kill.

I think general guidelines regardless of the method (e.g. dried, frozen, liquid preservative)  would be to minimize the time between tissue collection and preservation, avoid prolonged exposure to direct sunlight, and stay away from formalin. They also sell buffers that are meant to stabilize DNA prior to extraction but I've never tried them.

If we're talking about blood, I would just extract the gDNA as soon as you can and elute in  0.1x TE  prior to long-term storage at -80 or -20. The small amount of EDTA present in 0.1x TE doesn't seem to have an adverse effect on downstream sequencing. However, if the blood must be stored, it should be in EDTA at -80 and even then you'll likely have decreased yield and probably fragmentation depending on how long it sits. I haven't tried storing blood long-term with FTA cards.

For other tissues (e.g. lymph nodes, spleen, liver, lung, etc.), I've had good luck extracting HMW gDNA (and RNA) from decade-old material stored at -20 in RNAlater.

One easy, reliable and economic method is to preserve the tissues for DNA with higher integrity and further extraction is in ethanol 70% (liquid exceeding the volume of the tissue 2X) in a normal freezer (-20ºC).