I dont know how you lost the screws all, but anyway in Toshiba Laptop before they have Type of screw in each hole of the laptop F8 is a common screws of them outside the case, inside screws like mounting the Motherboard are short 3mm to 4mm, it depends you have to be very carefull when choosing the right screws as it may damage the board if you wrongly use long screw, you can buy in Amazon the universal screws just make sure to gauge the length you need before forcing a long screw that will hit your motherboard. I hope this helps you out. Good luck.
here is the link
https://www.amazon.sa/-/en/Anself-300Pcs-Screws-Universal-Computer/dp/B08BG5NNJW/ref=asc_df_B08BG5NNJW/?tag=sashogostdde-21&linkCode=df0&hvadid=453186851945&hvpos=&hvnetw=g&hvrand=3281022152861854631&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9077004&hvtargid=pla-1102838879979&psc=1