Household fly and ant killers are usually something like tetramethrin or permethrin, both aren't particularly toxic to humans although might well make you vomit. I have no idea what gfuel is, it sounds like a Google product... But assuming you mean gasoline (petrol) then again, it's certainly possible to overdose but there are unpleasant side effects (your stomach will give you a vision of hell for your trouble). Piercing and stabbing with sharp objects are rarely fatal methods of suicide (as far as the research I've encountered over the years), but are more commonly associated with self-harm, again, assuming you did exsanguinate - it's not a pleasant way to go unless you know exactly where to stab (this was the preferred method of a doctor I knew but not recommended for a layman).
Accidentally falling would depend on the height of the fall and the surface on which you fell. I wouldn't recommend it as some form of plausible deniability to your suicide attempt, what we might be convinced looks like a totally accidental fall would quickly reveal itself to be suicide to an experienced investigator or coroner.
As for rotten food, I've actually just written about forty something pages on how most rotten food isn't actually that harmful. With some foods there is a risk of acquiring a bacterial infection which would lead to food poisoning, some of these can be serious and fatal and dehydration is easily possible, but again those are deeply unpleasant, protracted and above-all else unreliable ways to go. I've certainly never heard of teabags being used as a fatal suicide method, but if we're taking this to the extreme then with some minor sedation you could technically choke yourself using the teabags - there have been cases, but once more, very, very, very unreliable and deeply unpleasant (you can see the pattern here).
There are some very effective and importantly, peaceful methods documented on this site. I know that you're desperate, I can see that in your post, but take a breath and spend a little time now to do some research. The time you spend now will not only let those impulsive and desperate thoughts pass, because suicide should never be committed on a whim; it will ensure that you don't put yourself through a bout of horrendous pain in hospital following a failed attempt, and believe me I think most nearly everyone here (myself included) have done very stupid and desperate things in pursuit of suicide at one point or another in our lives, I would urge you to step back and not fall into that same trap.
