You can use hashcat to do so. You can write rules that will operate on your given wordlist (in this case, the single word "PleaseSub!", however it can be as many as you please) and generate a bunch of similar passwords according to your rules. e.g
sXY - s will replace X with Y
$X - will append the character X to your wordlist
^X - will prepend the character X to your wordlist
and so on, that link I provided will give you a bunch of different commands and how to utilise them effectively.
se3 # Replace e with 3
sl1 # Replace l with 1
$1 # Append 1 to the generated password
$2 # Append 2 to the generated password
$3 # Append 3 to the generated password
Which can then be called like so
hashcat --stdout -r please_sub.rule base_word.txt
You can add multiple rules to a single line to have them all executed at the same time. E.g.
se3 sS5 $7
and the output becomes:
You can skip generating the wordlist and just call it directly like so
hashcat -m <mode> hash.file base_word.txt -r please_sub.rule
Writing your own rules can be quite difficult, so a helpful hint if you're trying this on Kali there are a bunch of pre-built rules in
hashcat -m <mode> hash.file base_word.txt -r /usr/share/hashcat/rules/best64.rule
This is not an exhaustive list and I encourage you read through the page I sent you for a much more in depth look at generating rules.