I've found that a very good way to expand one's collection of very versatile and handy tools is to find some of the great bargains available in surplus used tools.
Some tools may not still pass certifications for their original intended uses, but a well designed, quality, durable tool can still be utilized effectively for other purposes.
Some of the specific-use, commercial or areospace hand crimp tools from AMP, T&B, Hirose, Daniels, and many other quality tool manufacturers can cost over $800 each when checking new prices ($300-400 is common).
Many types have hardened precision-machined jaws, forged steel frames, compound action handles for ease of use to apply serious force to the workpiece, adjustability in the mechanism for recertification or custom applications.
Numerous brands of tools are intended for bare, flagged/tabbed U-shaped contacts, form (3-shaped closures where the ends of the tabs are forced to point into the center as the crimp is completed.
Many tools for insulated terminal applications form diamond-shaped, W-shaped, () flattened-round shapes or U-shaped impressions.
Daniels, Winchester, Buchanan and others typically have 4 radially oriented pin-jaws to crimp inward on bare cylindrical connector terminals.
Hex crimpers deform round metal shapes to the extent that there is essentially zero spring-back, ensuring a permanent, very secure grip.
One should never have unreasonable expectations of using an improvised crimp for anything related to proper electrical connections or mechanical safety-related applications/items, but for general purpose utility-type uses, a crimped metal sleeve may be far more practical than a knot or fastener.
Gamefish anglers have been using crimp sleeves on their lure leaders and tackle for generations.
Some folks are satisfied with using a hammer to close metallic tubular part onto another material, and call it done. I know there are numerous RCM'ers that enjoy using a little more finesse, and achieving repeatable, results that exhibit a more skillfully executed appearance, in most things they do.
The two common types of frame styles are F-style, where the user has easy access to various crimp nests/jaws at the open part of the F. The enclosed-head style of frames o= require the user to insert the terminal into the opening from the side, and then take the terminal out from the same side.
One could see that the F-style crimp tool could fairly easily be modified to set small, soft rivets, brass grommets or pins, near the edges of materials (sheetmetal) by a few modifications to the existing jaws, or making a replacement jaw set. Jaws could be fabricated which can deform small sections of soft wire into miniature rivets.
The heavy duty F-style forged steel frames are essentially a Roper-Whitney-type punch frame with a 90 degree head.. fairly easily modified to use as a punch. These F-style frames are a portable, miniature presses that can be modified for a multitude of bending pressing or forming tasks.
I've been finding numerous examples of the very durable, versatile hand crimp tools on eBay for $10 plus a little shipping, or less.
There are usually an abundance of commonly available materials to use for crimping. Brass, copper, aluminum or thin steel tubing or metallic eyelets, etc.
Crimping a sort length of tubing onto the ends of small diameter wire rope (garage door cable) will ensure that the end doesn't get frayed. Copper, brass or nickel silver tips on your shoelace ends, if you'd care to.
I suspect that there are a wide variety of uses for many of the durable, slightly worn, surplus deal crimp tools.