I'm part of a project that is replacing an oracle forms app with a web-based solution (javascript using React). We have the "keyboard-centric" UI requirement that you described. We have some interesting auto-completes - In a date field, if the user types an integer from 1-last day of month, and hits Tab, the date is automatically completed to include the current month and year. - On floating point numeric fields, if the user types a period on an empty field, a "0" is automatically pre-pended - We have LOV (list of values) field that allows the user to press F9 to get the list displayed where he can then select one of the values and press return. If he types a value that isn't in the list, and presses Tab, the list of values is displayed with the nearest matching value pre-selected. Curiously, we don't have hot-keys for button presses. I brought it up, citing the keep-them-on-the-keyboard paradigm, but was unceremoniously shot down. I don't make UI suggestions any more.
".45 ACP - because shooting twice is just silly" - JSOP, 2010
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You can never have too much ammo - unless you're swimming, or on fire. - JSOP, 2010
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When you pry the gun from my cold dead hands, be careful - the barrel will be very hot. - JSOP, 2013