The most important reserve to start is a cash reserve. Your reserve for unexpected emergencies requiring cash payout needs to be in liquid investments. That means it could be in the form of cash itself, a checking or savings account where it can be withdrawn quickly, or even a money market account. With each of these, the interest earned increases ever so slightly. Cash in your house will earn nothing, while cash invested in a money market account may earn dividends slightly larger than what you may get from a savings account at a bank or credit union. All of these locations are liquid and allow you to access the cash when it is needed. My rule of thumb is to keep enough cash in these locations to live off of for at least 3 to 6 months if you were to have no income. The amount will differ for everyone based on their spending habits. This will allow 3 to 6 months to find another source of income, most commonly to replace a lost job, or provide for a large unexpected payout without other consequences.
Having enough cash on hand will bring greater peace of mind, knowing that when the unexpected comes along you will have enough cash to get by without falling into a more difficult situation.