I'm not as familiar with Canadian tax laws around capital gains as I am US laws. Here stock dividends are taxed at a lower rate than bond income and gains on stocks aren't taxed until you sell them and then they are still taxed at a lower rate. From what I've read the rules aren't exactly the same in Canada, but they are close enough the same logic would apply. Conclusion: stock index funds are tax efficient. Bond funds are not.
Vanguard S&P 500 ETF (VOO)
Vanguard small cap
Vanguard Total Market
Vanguard International ex US
Leave these alone if they have any gains. These are all low cost tax efficient investments that belong in a taxable account. Yes, some of them overlap. If you caught it in advance you could do something about it. If they have gains now leave them alone.
In my opinion selling these funds at a gain so it 'appears' more simplified would be a big tax expense just to make your portfolio appear pretty. This is a huge waste of money.
Canadian Index ETF
Since you live in Canada you can probably assign the same logic here.
Oilfield Services ETF
I have no opinion. Sell it if you want.
Vanguard balanced (60% stocks, 40% bonds)
Vanguard Total Bond Market Fund
Barclays Aggregate bond market ETF (AGG)
I wouldn't want these in a taxable account. They go in a tax deferred account, and if you can shift your portfolio to get the bonds in a tax deferred account then it makes sense to sell them out of your taxable account even at a gain(in most cases). If you don't have a tax deferred account to move them to and they have gains, then you should probably leave them alone. Yes they overlap. Selling AGG at a gain and paying taxes just to put the money back into Vanguard Total Bond would be a big waste of money.
NOW, the good news! If we go through a down market you have a great portfolio for tax loss harvesting. As a matter of fact your portfolio looks like the result of past successful tax loss harvesting. ;) Simplify it then, when you can harvest losses(instead of realizing gains) in the process.
I also agree with everything MustahceAndAHalf said. In this case most of these investments are very low cost so unless your gains are miniscule the tax cost will likely be higher than the one or two basis points you might save on the expense ratios by shifting everything.
I think preferably I'd have a single bond market index fund, a US total market fund (VTI), and an international index fund that would represent a similar scenario to the mix of the above funds.
You can still do this with all of your future contributions.