Thanks for your reply, Mocacinno, I will definitely heed your warning. You said that maybe there are only one or two forks worth following up, would you care to name these please?
I'm still in two minds about selling, some days I have my doubts and start thinking I should just keep my Sats but most days I'm simply worried that a hacker will get them. I created the address in 2015 using bitaddress.org (a brainwallet) - and yes, surprisingly the funds are still there, luckily, I used a pretty complex sequence of words and symbols, which I find far easier to remember than a 24 word mnemonic plus passphrase. But I'm concerned because computers are getting more powerful, providing hackers with greater resources. It's in a legacy address as well, and I've heard that these are less secure (don't know if that's true or not).
Sure, i can name those forks... But let's be clear from the beginning: this is NOT an endorsement... Some of those forks are made by some really shady people (not going to name names here), some forks are insecure... I'm just looking at which ones would be worth your troubles of going trough the claim process and selling them on an exchange...
BCH is worth little over $200/BCH... So if you have more than 0.5 BCH, it might be worth looking into...
BSV is worth little over $150/BSV... So same thing, if you have >0.5 BSV, it might be worth claiming and selling them.
BTG, BTC, BTX, GOD and SBTC are worth between $10 and $1.... If you own more than $100 worth of these coins, it might be ok to sell them.
All the rest is <$1/coin, i wouldn't risk anything, nor spend time selling them at this point in time myself... In the (very, very, very) small chance their exchange rate would ever go upwards in the future, you still own those unspent outputs on those chains... Claiming forked coins is not time limited, as long as the coin is live, you own those unspent outputs...
Before attempting to claim, read my previous post (the text in bold, red letters)!
As for your second question: on a technical level, a legacy address is not less secure.... BUT, a brainwallet IS!!! So, in your case, it might actually be a good idear to move your funds to a decent wallet... It's the first step in the claim process of those forks anyways: move you funds to a new BTC wallet, and only afterwards claim the forks...
Which wallet to chose from depends greatly on your situation: are you going to get out of the crypto community and sell all your assets, or are you going to keep some? How much are we talking about (don't post a number on this forum)? How long will you be holding? What's your technical level of expertise? Do you have an older pc laying around?